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Fossil collecting in the southern states

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MikeR

Caloosahatchee 2015

A topic early last year in the Fossil Forum asked “What are your goals for 2015”. My response in that discussion was a desire to collect from the Duplin Formation in South Carolina to expand upon the species list within my Pliocene Project. Although I did not have the opportunity to bring those specific goals to fruition, I did add significantly to that list with unplanned collecting trips to two sites exposing the Golden Gate Member of the Tamiami Formation containing a number of species not found within the Pinecrest Member further north. However more so than any other unit that I sampled in 2015, was the unexpected opportunity to collect from several localities exposing the Lower Pleistocene (Gelasian) Caloosahatchee Formation. As I have previously reported the Caloosahatchee contains a mostly tropical fauna containing many endemic mollusks which lived within the flooded Everglades Basin following a 200,000 year sea level regression marking the end of the Pliocene Epoch.

My previous collecting endeavors in the Caloosahatchee had been restricted to the western portion of the Everglades/Big Cypress region and the trip that I attended in January 2015 organized by the Conservancy of Southwest Florida followed that trend with a visit to a quarry in Charlotte County (Fig. 1). The mine contained massive spoil piles of shell rich material excavated years ago that had undergone heavy weathering. As a result the large well preserved gastropods which the Caloosahatchee is known for were lacking although the weathering did reveal many of the smaller species not commonly looked for by most collectors.

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Figure 1. Locality 1039. Charlotte County, Florida.

Throughout last year I conversed with several forum members and messaging with Dozer Operator (Thanks Jonathan!) finally led to a collecting trip to the eastern half of the everglades. Unlike the incredibly hot trip with FossilDAWG and jehussey the previous week, Tropical Storm Erika was moving offshore of the Florida peninsula ensuring a wet but more bearable day in the field. Navigating heavy rain squalls with the use of Jonathan’s weather phone app, we were able to miss most of the precipitation and visited among others that day two sites exposing the Caloosahatchee Formation. The first in Martin County east of Lake Okeechobee contained primarily Caloosahatchee material with some overlying Middle Pleistocene Bermont Formation from which I was able to score examples of the larger mollusks that the Caloosahatchee is known for while Jonathan collected some interesting vertebrate material probably originating out of the Bermont (Fig. 2). The second stop further south in Palm Beach County contained equal amounts of Caloosahatchee and Bermont sediments (Fig. 3).

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Figure 2. Locality 1045. Martin County, Florida.

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Figure 3. Locality 499. Palm Beach County, Florida.

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Figure 4. Some gastropods from the Caloosahatchee Formation of South Florida.

Both sites particularly the latter, demonstrate the difficulty in identifying fossils within the Florida Plio-Pleistocene. Each of the shell bearing units in South Florida contain endemic species found only within designated deposits, however as seen in my Tamiami Gallery a number of molluscan species survived into recent times as well as some which persisted past the Upper Pliocene but becoming extinct later prior to the Holocene. Adding to the confusion are non-peer reviewed works which have taxonomically split new species based upon the unit and/or geographical region placing much emphasis on slight phenotypic variation. In the list below, I have attempted to be as accurate as possible in assigning species that belong in the Caloosahatchee, however short of in-situ collection there could be species particularly those collected from locality 499 that could have originated from the Bermont Formation. In addition, the below list also is the first that I have produced using marine invertebrate taxonomy as presented by the World Register of Marine Species (WoRMS) . This includes bivalve taxonomy proposed by Carter et. al., 2011 and gastropod taxonomy from numerous researchers. As shown in the list, not all of the gastropod families have been assigned to specific Orders and are waiting further study and DNA analysis. I will be applying the same classification to my other Plio-Pleistocene faunal lists as I update them in future posts.

Caloosahatchee species list 040416.pdf

References

Joseph G. Carter, Cristian R. Altaba, Laurie C. Anderson, Rafael Araujo, Alexander S. Biakov, Arthur E. Bogan, David C. Campbell, Matthew Campbell, Chen Jin-hua, John C. W. Cope, Graciela Delvene, Henk H. Dijkstra, Fang Zong-jie, Ronald N. Gardner, Vera A. Gavrilova, Irina A. Goncharova, Peter J. Harries, Joseph H. Hartman, Michael Hautmann, Walter R. Hoeh, Jorgen Hylleberg, Jiang Bao-yu, Paul Johnston, Lisa Kirkendale, Karl Kleemann, Jens Koppka, Jiřź Kříž, Deusana Machado, Nikolaus Malchus, Ana Márquez-Aliaga, Jean-Pierre Masse, Christopher A. McRoberts, Peter U. Middelfart, Simon Mitchell, Lidiya A. Nevesskaja, Sacit Özer, John Pojeta Jr., Inga V. Polubotko, Jose Maria Pons, Sergey Popov, Teresa Sánchez, André F. Sartori, Robert W. Scott, Irina I. Sey, Javier H. Signorelli, Vladimir V. Silantiev, Peter W. Skelton, Thomas Steuber, J. Bruce Waterhouse, G. Lynn Wingard and Thomas Yancey. 2011. A Synoptical Classification of the Bivalvia (Mollusca). Paleontological Contributions (4):1-47. 2011

MikeR

The Tamiami Fossil Reefs

Belying its status as the third most populous state in the nation and America’s self-proclaimed vacation wonderland, Florida was perhaps the last paleontological frontier in the lower 48 states. South Florida in particular was thought of as a vast impenetrable swamp and it was not until the Academy of Natural Sciences 1886 scientific expedition led by Angelo Heilprin along Florida’s southwestern coast and interior that it was discovered that South Florida until quite recently was submerged. It was along a cut channel on the Caloosahatchee River that Heilprin found vast deposits of fossil shells similar to but in many ways different than the modern molluscan fauna found on the coasts today. He named these beds the Caloosahatchee Marl and later workers expanded upon his work describing similar shell beds below the Caloosahatchee (Tamiami/Pinecrest) and above (Bermont Formation) each holding unique faunas. Geologists through much of the 20th century described these beds as an example of layer cake stratigraphy, a geologically inert region in which sediments are deposited upon each other like layers of a cake. This interpretation however was shown to be more complex in the late 70s when Jack Meeder, a doctoral student at the University of Miami, first described zonated fossil reef tracks found during the construction of the Golden Gate housing development east of Naples, Florida. Later in the 80s Ed Petuch described a similar coral rich fauna west of Miami during construction of the Meadows of the Lake housing development on Bird Road as well as in the west near Immokalee in the Mule Pen Quarry. The molluscan fauna, particularly that at Bird Road, contained species found in the Duplin Formation of the Carolinas suggesting a Late Pliocene age. Petuch correlated these coral reefs which ringed the southern Florida peninsula with Pacific island atolls. By definition an atoll is a ring of coral reefs surrounding a lagoon formed by the collapse of an inactive volcano. Although not fitting this description, he named these coral reefs a psedoatoll for the lagoon they formed and which through land building on top of the Pliocene coral reefs would one day impound the Everglades Basin forming the southern rim of the Florida Pennisula. The coral facies would eventually be grouped as a member of the Tamiami Formation by Missimer (1992) and named the Golden Gate Member. Petuch has commented that the Golden Gate has as many as 120 different coral species (in his publications he lists about half that number), more than any other fossil deposit of any age in the United States with an interesting mix of corals also found in the Pinecrest, Cuba and Dominican Republic Pliocene and the Lower Pleistocene Caloosahatchee (http://nmita.iowa.uiowa.edu/nmita/generaList.page?classification=NMITA&taxonName=Zooxanthellate+Coral&getGenButton=Get+Genera).

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Figure 1. Corals from the Golden Gate Member of the Tamiami Formation.

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Figure 2. Mollusks from the Golden Gate Member of the Tamiami Formation.

In the construction of my Pliocene Project, it has been my desire for the past several years to sample deposits which could expand upon the fauna list that I have been compiling. In 2014 that included collection from the latest Piacenzian deposits in the Chowan River Formation in North Carolina. This year the plan was to increase my collection of the Duplin Formation from South Carolina which has been limited so far to two localities in Bladen County, North Carolina, however a hectic work schedule had kept me from that goal. I always thought that the Golden Gate member would be out of my reach in the foreseeable future as many of the quarries that mined the member such as Mule Pen had closed and Florida had gone through a devastating housing bust. That dream however became a reality when conversations with forum member jehussey revealed the existence of two exposures in Collier County, one an old spoil pile still collectable and lake construction for a new housing development, the other. A business trip to South Florida allowed me to meet up with Jim, a retired geologist, for a brief exploratory trip to the sites. This led to an extended vacation the following month where we could collect more extensively at the new site (Locality 1043). In addition we had the added pleasure of meeting up with FossilDawg who happened to be in Fort Lauderdale for a conference and whose extensive knowledge of paleontology and biology along with Jim’s geology background led to one of the more enjoyable trips that I ever had pleasure to attend.

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Figure 3. Locality 1043. Golden Gate Member of the Tamiami Formation, Collier County, Florida.

In July, Jim and I explored an old site (Locality 1044) which was dug to form lakes in a housing development in the early 2000s. Although heavily stained by the elements this site exhibits the classic nature of the Golden Gate member; partially lithified carbonate sediments indicative of reefs rich in scleractinian corals and mollusks preserved whole and as internal casts. The back end of the new construction site (locality 1043) that we briefly visited that day was much fresher with excellently preserved Pliocene shells and solitary corals as well as echinoids and shells suggesting some earlier Pleistocene deposits on top of the Golden Gate. One month later, the morning Don and I headed out from Fort Lauderdale across the Everglades to meet with Jim, the day was projected to be a scorcher, well into the upper 90s. When we all met and headed to the new construction site, the lake excavation was well underway exposing much more material than Jim and I had seen the prior month and although unbearably hot we all collected many invertebrate specimens from the Golden Gate. In his description of the Everglades Pseudoatoll, Petuch diagramed a zonated reef track reminiscent of a true atoll with a high energy reef crest containing low encrusting corals, a reef platform with large coral heads and the quiet back reef with solitary corals. The two sites we collected suggest this interpretation as the older site contained coral species indicative of the reef platform while the new site was rich in solitary species found in the back reef. Later we retired to Jim’s place for cold drinks and to marvel at the material Jim had collected from the older site when productive, many of which he kindly donated to Don and I and which contributed to the list below.

Golden Gate species list 103115.pdf

Collecting from these sites demonstrate the difficulty in proper species identification due to the mixture of differentially aged sediments from the digging process. Some of the species that I found are indicative of later units for example Fasciolaria okeechobeensis which is a guide fossil for the Bermont Formation and the extant echinoid Clypeaster rosaceus which originates in the Caloosahatchee. Quite a few of the mollusks collected are known primarily from the Caloosahatchee however I cross referenced these with both the Neogene Digital Atlas (neogeneatlas.org) and the Florida Museum of Natural History Invertebrate Paleontology database (http://www.flmnh.ufl.edu/invertpaleo/search.asp) to find records of their existence in the Tamiami. Although I am not completely confident that these species are Pliocene or Pleistocene I have listed them for now in the Golden Gate list.

References

Meeder, J., 1979, Pliocene reef of SW Florida, a field guide with road log. Miami Geological Society Guidebook, 19 p.

Missimer, Thomas M. 1992. Stratigraphic relationships of sediment facies within the Tamiami Formation of Southwest Florida: Proposed intraformational correlations. Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Petuch, E. J. 1986. The Pliocene Reefs of Miami: Their Geomorphological Significance in the Evolution of the Atlantic Coastal Ridge, Southeastern Florida, U.S.A. Journal of Coastal Research 2(4):391–408.

Petuch, Edward J. 1987. The Florida Everglades: A Buried Pseudoatoll? Journal of Coastal Research 3(2): pp. 189-200.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Petuch, Edward J. 2007. The Geology of the Everglades and Adjacent Areas. CRC Press.

Weisbord, Norman E. 1974. Late Cenozoic Corals of South Florida. Bulletins of American Paleontology 66 (285) 544 pp.

MikeR

Pliocene Project Part 2

Part of the fascination with fossil shells is the excellent preservation which occurs under the proper conditions. With the exception of color, specimens whether shell, coral, or echinoderm, many times look as if they were picked off of a beach. Yet careful examination reveals differences between fossil and recent related species which demonstrate changes within taxa through time. Often overlooked however, are the geological processes which form shell beds. A principle of global geology is transgressive/regressive sea level rise. During warm periods, less water is captured in ice caps and glaciers resulting in a rise of sea level. As oceans encroach upon dry land (transgression) marine environments move accordingly and remains of organisms become deposited within building sediments. The process is not linear but gradual and the remains of these organisms are concentrated through currents and storms in dense accumulations by the process known as winnowing. As water levels continue to rise, the shallow marine zones which contain the most abundant life move according to optimum depth. Sediments continue to accumulate but into zones containing few macro organisms. When global temperatures drop, water is once more captured in ice and a regression of the oceans occur which remove sediment as sea levels retreat sometimes removing fossiliferous zones created during the previous transgression. When the next transgression cycle occurs, shell bed formation can be deposited on top of an older bed resulting in a time gap or unconformity. In Florida, species identification based upon age is particularly difficult where the southern most part of the state is only a few feet above sea level and fossils can only be obtained from quarries in which mining might go through several different beds producing specimens out of spacial context (fig. 1).

 SMR 4.jpg SMR 2.jpg SMR 3.jpg

Figure 1. SMR Aggregates Phase 10 Pit, Sarasota County, Florida. November 2013.

During the late Pliocene one such period of warming produced shell beds worldwide which can be correlated as to age on the basis of calcareous nanofossils and magnetostratigraphy. This period is called the Piacenzian stage based upon the incredibly rich shell beds near the Italian city of Piacenza. During this period Italy was no more than a sliver of land with the Adriatic reaching as far west as Turin. In northern Europe the English Channel was much wider as sea levels flooded west to London and eastward over much of the Netherlands and East Flanders. There was not a arctic ice cap and sea otters ranged up to the northern shore of Alaska where their fossilized remains have been found. In the Southern Hemisphere, the high southern shore of Australia was flooded as much of the Nullabor Plain was a shallow sea (fig. 2).

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Figure 2. Selected Piacenzian Gastropods. From left to right: Aphorrais pespelecani (Linne, 1758) Piacenzian Stage, Valchiavenna, ITALY; Nassa reticosa J.Sowerby, 1815, Red Crag Formation, Walton-on-the-Naze, Essex, UK; Cassis fimbriata Quoy & Gaimard, 1833, Roe Calcaranite, Madura, Western AUSTRALIA; Opalia varicostata anomala (Stearns, 1875), San Diego Formation, San Diego County, California USA.

The main regional geological event in North America just prior to the Piacenzian was the final closure of the Central America isthmus which forced warm equatorial waters up the North American eastern seaboard producing a local marine mass extinction. The Atlantic Ocean flooded the Salisbury Embayment covering much if not all of the Delmarva Peninsula, eastern Maryland and Virginia almost to the fall line in northeastern North Carolina. The shell beds formed here are referred to as Zone 2 Yorktown Formation. Further south the Western Atlantic extended from a line west of Robeson, North Carolina; Florence, South Carolina; the Okefenokee Basin in Georgia and Jacksonville, Florida. A secession of beds were laid down in this area during the Piacenzian, the best known being the Duplin Formation. The northern Gulf of Mexico reached almost to the Georgia state line depositing the Jackson Bluff formation while in the flooded Everglades Basin, the Tamiami Formation was formed. All of these beds can be correlated to each other based upon the mollusk taxa that they share (fig. 3).

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Figure 3. Some Piacenzian index fossils of the class Gastropoda found within the Southeastern United States. From left to right: Pterorytis umbrifer (Conrad, 1832), Moore House Member of the Yorktown Formation, Chucatuck, Isle of Wight County, Virginia; Sconsia hodgii (Conrad, 1841), Duplin Formation, Bladen County, North Carolina; Ecphora quadricostata (Say, 1824), Jackson Bluff Formation, Alum Bluff, Liberty County, Florida; Fasciolaria rhomboidea Rogers, 1839, Pinecrest Member of the Tamiami Formation, SMR Phase 10, Sarasota County, Florida.

This post represents an update to my Pliocene Project which I began in early 2012 resulting in a species list in 2013 of my Upper Pliocene collection organized and cross-referenced according to species found across the southeastern United States. Between that initial compilation and this one, however, I found that the methodology in which I performed identification was flawed. It is easy enough identify species one location at a time and to organize a collection by horizon, however when I began looking at those identifications side by side I found that there were errors. To rectify the discrepancies I reorganized my collection taxonomically as opposed to stratigraphically. Although this led to a great deal of invested time, the deep dive into taxonomy using descriptions within the original references has improved the accuracy and the confidence that have with the phylum mollusca, which I like to refer to as the “insects of the sea” based upon their numerical diversity. The expansion of the Piacenzian species list below includes the additions from my collecting efforts in the Tamiami Formation in 2013 and from the Chowan River Formation in 2014. A few corals, mollusks, and vertebrates were added to the list from the Pinecrest however the list was significantly increased with mollusks from the Chowan River Formation which introduced a number of Lower Pleistocene mollusks which first appeared towards the end of the Pliocene.

Piacenzian species list 020115.pdf

My plan is to periodically update the list as I will continue to collect within the Piacenzian particularly at SMR prior to its closure. Also on tap for 2015 is a concerted effort to investigate Duplin deposits in the Carolinas which contain many endemic species and is represented in my collection from only two localities.

Although I have previously listed many of the references below these are the ones that I have used the most for species identification. The website for the World Register of Marine Species (WoRMS) has been particularly useful for providing the most updated names of mollusk genera.

REFERENCES

Bouchet, P., Yu. I. Kantor, A.Sysoev and N. Puillandre. 2011. New Operational Classification of the Conoidea (Gastropoda). Journal of Molluscan Studies (2011) 77: 273–308.

Campbell, Lyle. 1975. Check List of Marine Pliocene Mollusks of Eastern North America in Plio-Pleistocene Faunas of the Central Carolina Coastal Plain. Geologic Notes (South Carolina Division of Geology) Vol. 19, No. 3.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Dall W.H. 1890-1903. Contributions to the Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchie River, Part I: Pulmonate, Opisthobranchiate and Orthodont Gastropods, Transactions of the Wagner Free Institute of Science of Philadelphia 3(1-VI).

Gardner, J. A. 1944. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 1. Pelecypoda, United States Geological Survey Professional Paper 199-A: iv, pages 1-178, plates 1-23

Gardner, J. A. 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 2. Scaphopoda and Gastropoda, United States Geological Survey Professional Paper 199-B: iv, pages 179-310, plates 24-38, [iii]

Gardner, J. A. and T.H. Aldrich. 1919. Mollusca from the Upper Miocene of South Carolina: with Descriptions of New Species. Proceedings of the Academy of Natural Sciences of Philadelphia 71: pages 17-53.

Gibson, Thomas G. 1987. Miocene and Pliocene Pectinidae (Bivalvia) from the Lee Creek Mine and Adjacent Areas in Geology and Paleontology of the Lee Creek Mine, North Carolina, II. Smithsonian Contributions to Paleobiology No. 61.

Hendricks, Jonathan. 2008. The genus Conus (Mollusca: Neogastropoda) in the Plio-Pleistocene of the southeastern United States, Bulletins of American Paleontology 375.

Hulbert, Richard C. (ed.). 2001. The Fossils Vertebrates of Florida. University Press of Florida.

Mansfield, W.C. 1930. Miocene Gastropods and Scaphopods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 3, 189 pages.

Mansfield, W.C. 1931. Some tertiary mollusks from southern Florida. Proceedings of the United States National Museum, v. 79.

Mansfield, W.C. 1931. Pliocene Fossils from Limestone in Southern Florida in Shorter Contributions to General Geology, USGS Professional Paper 170, 11 pages.

Mansfield, W.C. 1932. Miocene Pelecypods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 8, 233 pages.

Mansfield, W.C. 1936. Stratigraphic Significance of Miocene, Pliocene, and Pleistocene Pectinidae in the Southeastern United States, Journal of Paleontology, Vol 10, No. 3, 24 pages.

Mansfield, W.C. 1939. Notes on the Upper Tertiary and Pleistocene Mollusks of Peninsular Florida, Florida Geological Survey Bulletin 18, 128 pages.

Hollister, S.C. 1971. New Vasum Species of the Subgenus Hystrivasum. Bulletins of American Paleontology 262.

Olsson, A.A. 1967 (1993 Reprint). Some Tertiary Mollusks from South Florida and the Caribbean, Originally - Bulletins of American Paleontology 54(242), The Paleontological Research Institute Special Publication 19: pages 11-75, 9 plates

Olsson, A.A., and A. Harbison. 1953 (1990 Reprint). Pliocene Mollusca of Southern Florida with Special Reference to Those from North Saint Petersburg, with special chapters on Turridae by W.G. Fargo and Vitinellidae and Fresh-water Mollusks by H.A. Pilsbry, The Academy of Natural Sciences of Philadelphia Monographs 8, The Shell Museum and Educational Foundation, 457 pages, 65 plates

Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217): pages 509-574, plates 77-83

Olsson, A.A., and R.E. Petit. 1968 (1993 Reprint). Notes on Siphocypraea, Originally - Special Publication 9, The Paleontological Research Institute Special Publication 19: pages 77-88.

Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.

Portell, Roger W. and Craig W. Oyen. June 2002. Pliocene and Pleistocene Echinoids. Florida Fossil Invertebrates Part 3, 30pp.

Portell, Roger W. and Jeffery G. Agnew. February 2004. Pliocene and Pleistocene Decapod Crustaceans. Florida Fossil Invertebrates Part 4, 29 pp.

Portell, Roger W. November 2004. Eocene, Oligocene and Miocene Decapod Crustaceans. Florida Fossil Invertebrates Part 4, 29 pp.

Rathbun, Mary J. 1935. Fossil Crustacea of the Atlantic and Gulf coastal plain. Geological Society of America. Special papers; no. 2.

Tucker, H.I. and Druid Wilson. 1932. Some new or otherwise interesting fossils from the Florida Tertiary. Bulletins of American paleontology; v. 18: no. 65.

Tucker, H.I. and Druid Wilson. 1933. A second contribution to the Neogene paleontology of South Florida. Bulletins of American paleontology; v. 18: no. 66.

Tuomey, M., and F.S. Holmes. 1855-1856 (1974 Reprint). Pleiocene Fossils of South-Carolina: Containing Descriptions and Figures of the Polyparia, Echinodermata and Mollusca, Original pages 1-30 and plates 1-12 published in 1855, Original pages 31-152 and plates 13-30 published in 1856, The Paleontological Research Institution Special Publication 12: xvi, 152 pages, 30 plates, [addendum]

Turgeon, D.D. et al. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. Second edition. American Fisheries Society Special Publication. No. 26. 526 pp.

Waller, T.R. 1969. The evolution of the Argopecten gibbus stock (Mollusca: Bivalvia), with emphasis on the Tertiary and Quaternary species of eastern North America. Journal of Paleontology, Memoir 3 (vol. 43, suppl. to No. 5).

Ward L.W. and Blackwelder, B.W. 1975. Chesapecten, a New “Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. USGS Professional Paper 861.

Ward, L. W., and Gilinsky, N. L. 1993. Molluscan assemblage of the Chowan River Formation, Part A. Biostratigraphic analysis of the Chowan River Formation (Upper Pliocene) and adjoining units, the Moore House Member of the Yorktown Formation (upper Pliocene) and the James City Formation (Lower Pleistocene): Virginia Museum of Natural History Memoir 3, part A., 33 p.

Williams, Margaret. 2006. Shallow-Water Turridae of Florida and the Caribbean. Self published.

Weisbord, Norman E. 1966. Some late Cenozoic cirripeds from Venezuela and Florida. Bull. Amer. Paleont., vol. 50, no. 225, pp. 1-145, pls. 1-12.

Weisbord, Norman E. 1974. Late Cenozoic Corals of South Florida. Bulletins of American Paleontology vol. 66, no. 285. 544 pp.

Zullo, Victor A., 1992. Revision of the balanid barnacle genus Concavus Newman. Supplement to Journal of Paleontology, v. 66, no. 6, pt. II.

Zullo, Victor A. and Portell, Roger W. 1993. Paleobiogeography of the Late Cenozoic Barnacle Fauna of Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

WEBSITES

The Bailey-Matthews National Shell Museum Southwest Florida Shells http://shellmuseum.o.../shellindex.cfm

Florida Museum of Natural History Invertebrate Paleontology Database http://www.flmnh.ufl.edu/invertpaleo/search.asp

Florida Museum of Natural History Invertebrate Paleontology Image Gallery http://www.flmnh.ufl.edu/invertpaleo/galleries.htm

Fossilworks, Gateway to the paleobiology Database http://fossilworks.org/

Gastropoda Stromboidea http://www.stromboidea.de/?n=Main.HomePage

Greta L. Polites Worldwide Fossil Muricidae Collection http://glpolites.us/murex/index.htm

International Fossil Shell Museum http://www.fossilshells.nl/

Let’s Talk Seashells http://www.letstalkseashells.com/

Natural History Museum Rotterdam Mollusks Database http://www.nmr-pics.nl/

The Neogene Atlas of Ancient Life Southeastern United States http://neogeneatlas.org/

Olividae and Olivellidae Lifedesk – Mollusca http://olivirv.lifedesks.org/

The World Register of Marine Species (WoRMS) http://www.marinespecies.org/index.php

SMR 1.jpg

MikeR

Chowan River Formation Revisited

My first experience with the Chowan River Formation was during a collecting trip in 2011 to collect Zone 2 Yorktown sediments along the Roanoke River in North Carolina. The paltry fauna that I collected from the two Chowan sites stood in stark contrast to the molluscan-rich Yorktown Rushmere Member exposed further upstream. Since I had been writing about the Upper Pliocene deposits of the Eastern United States, I was looking forward to collecting these youngest Pliocene deposits but with a total of only 13 species, I was completely underwhelmed. So earlier this year when I had the opportunity to collect at the namesake exposures along the Chowan River as well as another on the Wiccacon River, I jumped at the chance.

The Chowan River Formation was named by Blake Blackwelder for shelly, silty sands deposited in northeastern North Carolina found primarily along the Chowan River and a few quarry exposures in southern Virginia. Early authors such as W.C. Mansfield had attributed these sites as Upper Yorktown while acknowledging that the deposits were stratigraphically higher i.e. younger than the traditional Yorktown. The Chowan fauna is notable for the lack of many of the key Yorktown taxa including Chesapecten, Chesacardium, Planicardium, and Ecphora. Sandwiched in between Zone 2 Yorktown and the James City Formation, the Chowan fauna is transitory between Pliocene and Pleistocene containing species from both. A world-wide cooling event occurring around 3 mya dropped sea levels resulting in the formation of the present Arctic ice cap and proved particularly devastating to the Yorktown fauna. When global temperatures warmed once more, the resulting Chowan River deposition contained a subtropical fauna which probably derived from the south. The result is that mollusks from the Chowan River Formation include Yorktown survivors, the first occurrence of the Gelasian fauna and endemics found only in the Chowan (fig. 1).

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Figure 1. Mollusks from the Chowan River Formation. Ptychosalpinx chesapeakensis, Martin County, NC and Crucibulum leeanum, Hertford County, NC make last appearance. Diodora pamlicoensis, Hertford County, NC and Crucibulum lawrencei, Bertie County, NC make first appearance. Costaglycymeris hummi, Bertie County, NC endemic to the Chowan River Formation.

The Chowan River itself originates near the North Carolina and Virginia border by the merger of the Blackwater and Nottoway rivers and along with the Meherrin River forms the main drainage basin for the Albemarle Sound. Fossiliferous deposits are found on the right bank of the river although not apparent from the left bank boat launch at US 17 due to the very wide nature of the river. The longest continuous deposits were at Edenhouse and Blackwelder named the lower fossiliferous-most member after the small town. All of those deposits are now graded over, planted and rip-rapped by riverside mansions. The closest sites from the marina are far upstream and can only be reached by boat. Most sites are current deposited sands with collecting consisting of picking mollusks weathered from the bluffs. Locality 1032 however, is siltier representing a gentle environment with many double-valved pelecypods, echinoids and a single great white shark tooth, very rare for this vertebrate poor formation.

The Wiccacon River is very different as it is not much more than a creek that feeds into the Chowan River. The lone site is at water level at the base of a bluff with a lot of overhanging vegetation that limits access to the exposure. The sand here however lends itself well to screen washing and I collected a 5 gallon bucket of ¼ inch sorted sediment which allowed me to collect smaller material from the comfort of home that I would have normally overlooked. Included within the washed material where assorted cheliped from six different crab species which I would guess as never being characterized from the Chowan. Above the sandy layer was a more resistant zone containing larger shells including many endemic Carolinapecten eboreus bertiensis and a single relatively well preserved specimen of Busycotypus concinnum which I put my pick through. This gastropod makes its first appearance in the Chowan River Formation and its last in the Lower Pleistocene James City and Waccamaw Formations. Blackwelder listed this site as basal Chowan River and screen washing did come up with some scrap Yorktown material that was probably redeposited (fig. 2).

blogentry-1906-0-37551500-1417024246.jpg blogentry-1906-0-88215700-1417024248.jpg blogentry-1906-0-97398600-1417024250.jpg

Figure 2. Locality 1028 on the Wiccacon River.

The species list below represents my collecting efforts from the youngest Pliocene exposed on the Chowan, Roanoke and Wiccacon Rivers in North Carolina containing 130 different species. The Chowan River Formation is dominated by mollusks but in addition I have collected bryozoans, corals, barnacles, crabs, echinoids and rare vertebrates within these deposits.

Chowan River species list 102214.pdf

REFERENCES

Bailey, R. H., 1977: Neogene Molluscan Assemblages along the Chowan River North Carolina. Southeastern Geology 18(3): 173-190.

Blackwelder, Blake W. 1981. Stratigraphy of Upper Pliocene and Lower Pleistocene Marine and Estuarine Deposits of Northeastern North Carolina and Southeastern Virginia. USGS Bulletin: 1502-B.

Blackwelder, Blake W. 1981. Late Cenozoic Stages and Molluscan Zones of the U.S. Middle Atlantic Coastal Plain. Memoir (The Paleontological Society) Vol. 12, Supplement to Vol. 55, no. 5 of the Journal of Paleontology (Sep., 1981), pp. 1-34.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Ward, Lauck W. 1993. Pliocene Stratigraphy and Biostratigraphy – Virginia to Florida in the Neogene of Florida and Adjacent Regions. Florida Geological Survey Special Publication No. 37.

Ward, Lauck W. 2008. Synthesis of Paleontological and Stratigraphic Investigations at the Lee Creek Mine, Aurora, NC (1958-2007) in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virgina Museum of Natural History Special Publication No. 14.

Ward, L.W. and Blackwelder, B.W. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group-Middle Atlantic Coastal Plain. USGS Bulletin 1482-D.

Ward, L. W., and Blackwelder, B. W. 1987. Upper Pliocene and lower Pleistocene mollusks of the Lee Creek mine, Aurora, North Carolina, in Ray, C. E., editor, Geology and Paleontology of the Lee Creek Mine, North Carolina, ?II: Smithson, Contrib. Paleobiol. 61:113-283.

Ward, L. W., and Gilinsky, N. L. 1993. Molluscan assemblage of the Chowan River Formation, Part A. Biostratigraphic analysis of the Chowan River Formation (Upper Pliocene) and adjoining units, the Moore House Member of the Yorktown Formation (upper Pliocene) and the James City Formation (Lower Pleistocene): Virginia Museum of Natural History Memoir 3, part A., 33 p.

MikeR

Smr Aggregates 2013

In early 2013 after two years of work, I finally completed the preparation, identification and curation of my extensive Upper Pliocene collection from the Eastern United States. My intent afterwards was to quickly use the same method to knock out my Pleistocene collection so I could start on a new large Cretaceous project. But as John Steinbeck once wrote “The best laid schemes of mice and men often go awry” applies here as I continued to add to my Pliocene collection throughout the remainder of 2013 and into 2014. Field work in 2013 included three trips to the SMR Aggregates quarry near Sarasota exposing the shell rich Pinecrest Sand and in 2014, five different sites of the latest Piacenzian Chowan River Formation in North Carolina. I originally intended to include both into the same post with an updated Upper Pliocene species list however this quickly became unfeasible because of the numbers of new species that I collected from both formations. As a result, this entry will concentrate on SMR and the next on the Chowan River.

As previously described in earlier posts, the Pinecrest Sand Member of the Tamiami Formation is an Upper Pliocene, mollusk-rich deposit exposed mostly in South Florida quarries which mine the shell and sand for road fill and construction. The Pinecrest is the most biodiverse geological unit in the United States and was formed by winnowing; a process in which mollusk shells are buried and re-exposed by currents and storms to form highly concentrated shell beds. The beds themselves have been classified into 11 units based upon lithology and certain mollusk species which tend to dominate specific beds. The mollusks are mostly a mix of tropical and subtropical species some of which are shared with contemporary deposits in the Florida Panhandle (Jackson Bluff Formation) and Mid-Atlantic region (Duplin and Zone 2 Yorktown Formations).

The SMR Aggregate quarries lie within Sarasota County just south of the Manatee County line. When I first began collecting the site in 2012, SMR was mining Bed 10 in the Phase 8 pit. Since then, all activity is westward in the Phase 10 pit, first mining into Bed 7 and then down to Bed 10 removing all shell and sand until Unit 11 is reached. In 2013 there was a flurry of field trips organized by various groups due to the impending closing, reclamation and development of the mine. As a result, I attended field trips organized at various time throughout that year by the Florida Paleontological Society, Conchologists of America, and the Southeast Geological Society.

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Figure 1. SMR Aggregates Phase 10 Pit, Sarasota County, Florida. Left two photos quarried down through Bed 7. Right two photos second bench quarried from Bed 8 to top of Bed 11.

In my initial posts about the Pinecrest, I had made much about the opportunity compare differences in individual beds that Ed Petuch used for describing new species with only subtle differences. My four trips to the quarry however has convinced me that this is impossible to do as the initial mining is through Bed 7 resulting in a mixture of Beds 1 to 7 and then mining down to the top of Bed 11 which is a mixture of Beds 1 to 11. As a result, my labels which state Bed 7 were merely found on the upper quarry bench and Bed 10, the lower (fig. 1).

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Figure 2. Selection of specimens collected in the 2013 field season.

As with any single locality repeated visitation has cut down on the amount of material that I bring home from SMR but has allowed me to become more selective of what I collect (fig. 2). My last trip to the quarry, I concentrated on vertebrates found within Bed 11 adding slightly to my Pinecrest fauna list. Reviewing my earlier posts concerning various Pinecrest horizons, I discovered that I had never produced an overall fauna list which is rectified below. In comparing this list with my previous Pinecrest bivalve and gastropod lists or of Tamiami species in my Pliocene project, one will notice that there are differences not only with the number of additions but also with the removal of some species. This was due to refinement with my identifications and the acceptance of some of Ed Petuch’s species both of which I will go into more detail when I update my Pliocene Project. The list contains all species that I have found within the Tamiami Formation including the limestone facies (Ochopee) and a few from the Kissimmee fauna. With the exception of only a handful of species, mostly echinoids, the vast majority can be found at SMR. The list is dominated by mollusks; 185 bivalves, 317 gastropods and 2 scaphopods and is probably less than 50 percent of what is estimated that can be collected in the Pinecrest.

Tamiami species list 102014.pdf

In the past, I have posted references but instead of duplicating past efforts, I have only included those that I have not previously listed.

References

Allmon, W.D., 1993, Age, environment and mode of deposition of the densely fossiliferous Pinecrest Sand (Pliocene of Florida): implications for the role of biological productivity in shell bed formation. Palaios, 8:183-201.

Ketcher, K., and W.D.Allmon, 1993, Environment and mode of deposition of a Pliocene coral bed: coral thickets and storms in the fossil record. Palaios, 8:3-17.

Portell, Roger W., Guy H. Means, Richard C. Hulbert Jr. 2012. SMR Aggregates, Inc., Sarasota, Florida. Southeastern Geological Society Field Trip Guidebook, Vol. 56, 24pp.

Stanley, Steven M. and William F. Ruddiman. 1995. Neogene Ice Age in the North Atlantic Region: Climatic Changes, Biotic Effects, and Forcing Factors in Effects of Past Global Change on Life, Studies in Geophysics. National Academy Press, Washington., D.C. pp 118-131.

MikeR

The glaciations which are a hallmark of the Pleistocene, actual began sometime in the late Pliocene. The extent varied but each of the three largest Ice Age glacial events produced noticeable marine fauna changes along the Western Atlantic coast. As temperatures warmed during the first major interglacial of the earliest Pleistocene, rising sea levels formed the rich shell beds of the Caloosahatchee, Waccamaw and James City Formations that we see today in the quarries and river bluffs in the Eastern United States. This transgression which flooded the older Piacenzian basins, introduced molluscan species which included Pliocene survivors and new species which evolved in an interval of less than hundred thousand years from the end of the Pliocene.

In much of the same manner that I compiled a fauna list of the Upper Pliocene species in my collection, I wanted to do the same for the Lower Pleistocene. However, as I began writing this installment, the Florida Museum of Natural History came out with the latest of their Florida Paleontological Society series on the invertebrate fauna of Florida; that of the marine mollusks of the Nashua Formation. The Lower Pleistocene Nashua was deposited along the Northern Florida Atlantic coast and found mostly in quarries and a few natural deposits along the St. Johns River. The most famous of the Nashua quarries was the Fort Drum Mine, known to fossil and mineral collectors alike for a bed of the clam Mercenaria permagna whose interiors were lined with calcite crystals. Although I never had the opportunity to collect in these quarries, I did acquire a few in trades to add to my fauna list (fig. 1). The Nashua’s molluscan fauna included an interesting mix of species from the northern Waccamaw and James City Formations, the southern Caloosahatchee Marl, as well as endemic species and forms. The six month delay between this and my last post was in part due to Nashua species shared between the different Lower Pleistocene formations described by Ed Petuch which I had considered synonyms to other species but are considered valid by FMNH in this latest publication. I still think that some of these are synonyms of previously described species but I do not have the large comparative collection to support my assumption so in most cases, although not all, I have accepted Petuch species which have been vetted by the Florida Museum of Natural History. As a result when comparing this comprehensive list of the Lower Pleistocene with species lists of the individual formations from my earlier posts, one will see some differences. My new list also includes updated generic names gleaned from the FMNH Nashua fauna list.

blogentry-1906-0-21659700-1402006324.jpg blogentry-1906-0-67633700-1402006349.jpg Figure 1. Gastropods from the Nashua Formation.

Also included within the list are James City Formation fossils found in exposures along the Neuse River in North Carolina that I did not include in my earlier post on the James City. Among the new additions are shark teeth and other vertebrates found from washed James City sediments that were thrown up by tides upon an Upper Pleistocene/Holocene bog exposure (fig. 2).

blogentry-1906-0-86387900-1402017705.jpg Figure 2. Locality 1035, Neuse River, Craven County, North Carolina.

The reasoning that I used for the systematic structure in my Early Pleistocene list is the same as in my Upper Pliocene list (http://www.thefossilforum.com/index.php?/blog/101/entry-233-the-end-of-my-pliocene-project/) and taxonomic classification is addressed in the notes section below. Abbreviations used in the list are James City (J), Waccamaw (W), Nashua (N), and Caloosahatchee (C ).

Gelasian species list.pdf

Notes

Bryozoa. With the exception of Hippoporidra edax with its diagnostic monitcules, most bryozoa in my collection are not listed to genus or species for the lack of adequate references.

Anthozoa. The Caloosahatchee Marl was deposited in a protected lagoon/marine environment in what was then the flooded everglades basin. Because of the shallowness of what Ed Petuch calls the Caloosahatchee Subsea, the super-heated water temperatures produced tropical conditions supportive of a diverse coral fauna. In contrast, the subtropical Waccamaw and warm temperate James City Formation contained only a few species which could tolerate cooler waters.

Mollusca. My latest list contains 139 species and subspecies of bivalves, 220 of gastropods and 4 scaphopods. These totals are lower than what I reported in my collection from the Upper Pliocene but part of the reason lies in the fact that I have collected from more Piacenzian than Gelasian localities. Studies led mostly by Warren Allmon now director at the Paleontological Research Institute reported that although extinction rates were high for Pliocene mollusks, origination rates for new molluscan species were also high. The number of mollusk species was very similar between the Caloosahatchee Marl and the older Tamiami Formation and for that of the Waccamaw compared to its older contemporary, the Duplin Formation. The exception was the James City Formation with its lower diversity compared to the earlier Zone 2 Yorktown. Anyone who had collected from the very shelly James City beds at the Lee Creek Mine might take exception with that fact however although the number of individuals was incredibly high, the diversity was much lower as the Upper Yorktown experienced periods of warm water molluscan invasions due to changes that were occurring in ocean currents from the final closure of the Isthmus of Panama during the Late Pliocene. For molluscan systematics, I continued to follow Turgeon et. al. with one exception. As I mentioned in my post about my Piacenzian collection, I was troubled about the listed classification of the subfamily/genera Glyphostoma and Cythara into the family Conidae. However in the one and half years since that post I discovered the work of Bouchet, et. al. with the superfamily Conoidea (drills, turrids, augers, cones) which based partially on DNA studies split Turridae into several families with Glyphostoma and Cythara into their own separate families.

Cirripedia. Balanid barnacles were very diverse in the Eastern US Upper Pliocene with no fewer than two different mostly endemic species each in the Tamiami/Duplin/Yorktown Formations. In comparison, I have collected only three barnacles, one species each from the Caloosahatchee/Waccamaw/James City formations. Identification was made by using the dominant species found within each of those formations within published literature.

Decapoda. Crabs remains are not uncommon in the Caloosahatchee and James City Formations but absent in my collection from the Waccamaw.

Echinoids. Unlike crabs, echinoids are common in the Waccamaw and I have collected their remains in the majority of Waccamaw localities that I have visited. Echinoids can be relatively common in the Caloosahatchee but are restricted to specific facies. The only echinoid that I have found in the James City Formation is Mellita aclinensis, a sand dollar that survived the Pliocene extinction.

Vertebrates. Upwelling of cold nutrient rich water is conducive for schooling fish and their predators and prior to the Upper Pliocene, water temperatures along the Western Atlantic were more similar to that now found along the Eastern Pacific. With the Closure of the Isthmus of Panama during the Upper Pliocene, the Western Atlantic was isolated from the cool Eastern Pacific and under the influence of the warm Caribbean. The result was lower productivity which could not support the diverse vertebrate faunas typified in earlier shell beds such as Bed 10 Calvert Formation, the Eastover Formation and Zone 1 Yorktown. Like the Upper Pliocene beds, vertebrates are not a large component in the Gelasian deposits of the Eastern United States. Of the Lower Pleistocene beds, the Caloosahatchee Marl contains the richest vertebrate fauna consisting of a mix of land and marine species which in my collection include fish, fresh/brackish reptile, cetacean, deer and the only reported instance of seal in the Caloosahatchee. During the dredging of the Intercoastal Waterway in Myrtle Beach, South Carolina during the late 70s/early 80s, a mix of Upper Cretaceous PeeDee and Lower Pleistocene Waccamaw were brought up in the spoil. Among the fossils were a land vertebrate fauna attributed to the Upper Pleistocene but could be Waccamaw. In the late 90s when I visited, some of the weathered spoil was still accessible where I found a horse tooth which I have tentatively listed as Waccamaw (W?) as well as a Hemipristis tooth which is not reported much past the Pliocene and also listed as tentative Waccamaw in my database.

REFERENCES

Many of the references that I used for my posts and identification of species in the Lower Pleistocene are the same as for the Upper Pliocene but smaller in number. This is because the Lower Pleistocene is much better characterized by monographs notably Olsson and Harbinson (Caloosahatchee), Gardner and Mansfield (Waccamaw) and Ward and Blackwelder (James City) than the Upper Pliocene particularly the Tamiami/Pinecrest. In addition to printed references, I have included websites typically affiliated with universities or museums that I have found useful in identification of species from this time period.

Websites

The Bailey-Matthews National Shell Museum Southwest Florida Shells http://shellmuseum.org/shells/shellindex.cfm

The Digital Atlas of Neogene Life: Southeastern U.S. http://www.geosun.sjsu.edu/~jhendricks/AtlasTemp/neogene.html

Florida Museum of Natural History Invertebrate Paleontology Database http://www.flmnh.ufl.edu/invertpaleo/search.asp

Florida Museum of Natural History Invertebrate Paleontology Image Gallery http://www.flmnh.ufl.edu/invertpaleo/galleries.htm

Gastropoda Stromboidea http://www.stromboidea.de/?n=Main.HomePage

Greta L. Polites Worldwide Fossil Muricidae Collection http://glpolites.us/murex/index.htm

International Fossil Shell Museum http://www.fossilshells.nl/

Let’s Talk Seashells http://www.letstalkseashells.com/

Natural History Museum Rotterdam Mollusks Database http://www.nmr-pics.nl/

Olividae and Olivellidae Lifedesk – Mollusca http://olivirv.lifedesks.org/

Identification

Campbell, Lyle. 1975. Check List of Marine Pliocene Mollusks of Eastern North America in Plio-Pleistocene Faunas of the Central Carolina Coastal Plain. Geologic Notes (South Carolina Division of Geology) Vol. 19, No. 3.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Dall W.H. 1890-1903. Contributions to the Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchee River, Transactions of the Wagner Free Institute of Science of Philadelphia 3(1-VI).

Gardner, J. A. 1944. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 1. Pelecypoda, United States Geological Survey Professional Paper 199-A: iv, pages 1-178, plates 1-23

Gardner, J. A. 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 2. Scaphopoda and Gastropoda, United States Geological Survey Professional Paper 199-B: iv, pages 179-310, plates 24-38, [iii]

Gibson, Thomas G. 1987. Miocene and Pliocene Pectinidae (Bivalvia) from the Lee Creek Mine and Adjacent Areas in Geology and Paleontology of the Lee Creek Mine, North Carolina, II. Smithsonian Contributions to Paleobiology No. 61.

Hendricks, Jonathan. 2008. The genus Conus (Mollusca: Neogastropoda) in the Plio-Pleistocene of the southeastern United States, Bulletins of American Paleontology 375.

Kittle, B. Alex, Roger W. Portell, Harry G. Lee and Sean W. Roberts. December 2013. Mollusca, Nashua Formation (Late Pliocene to Early Pleistocene). Florida Fossil Invertebrates Part 15, 40 pp.

Mansfield, W.C. 1932. Miocene Pelecypods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 8, 233 pages.

Mansfield, W.C. 1936. Stratigraphic Significance of Miocene, Pliocene, and Pleistocene Pectinidae in the Southeastern United States, Journal of Paleontology, Vol 10, No. 3, 24 pages.

Mansfield, W.C. 1939. Notes on the Upper Tertiary and Pleistocene Mollusks of Peninsular Florida, Florida Geological Survey Bulletin 18, 128 pages.

Hollister, S.C. 1971. New Vasum Species of the Subgenus Hystrivasum. Bulletins of American Paleontology 262.

Olsson, A.A. 1967 (1993 Reprint). Some Tertiary Mollusks from South Florida and the Caribbean, Originally - Bulletins of American Paleontology 54(242), The Paleontological Research Institute Special Publication 19: pages 11-75, 9 plates

Olsson, A.A., and A. Harbinson. 1953 (1990 Reprint). Pliocene Mollusca of Southern Florida with Special Reference to Those from North Saint Petersburg, with special chapters on Turridae by W.G. Fargo and Vitinellidae and Fresh-water Mollusks by H.A. Pilsbry, The Academy of Natural Sciences of Philadelphia Monographs 8, The Shell Museum and Educational Foundation, 457 pages, 65 plates

Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217): pages 509-574, plates 77-83

Olsson, A.A., and R.E. Petit. 1968 (1993 Reprint). Notes on Siphocypraea, Originally - Special Publication 9, The Paleontological Research Institute Special Publication 19: pages 77-88.

Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.

Portell, Roger W. and Craig W. Oyen. June 2002. Pliocene and Pleistocene Echinoids. Florida Fossil Invertebrates Part 3, 30pp.

Portell, Roger W. and Jeffery G. Agnew. February 2004. Pliocene and Pleistocene Decapod Crustaceans. Florida Fossil Invertebrates Part 4, 29 pp.

Portell, Roger W. and B. Alex Kittle. December 2010. Mollusca, Bermont Formation (Middle Pleistocene). Florida Fossil Invertebrates Part 13, 40 pp.

Rathbun, Mary J. 1935. Fossil Crustacea of the Atlantic and Gulf coastal plain. Geological Society of America. Special papers; no. 2.

Tucker, H.I. and Druid Wilson. 1932. Some new or otherwise interesting fossils from the Florida Tertiary. Bulletins of American paleontology; v. 18: no. 65.

Tucker, H.I. and Druid Wilson. 1933. A second contribution to the Neogene paleontology of South Florida. Bulletins of American paleontology; v. 18: no. 66.

Ward L.W. and Blackwelder, B.W. 1987. Late Pliocene and Early Pleistocene Mollusca from the James City and Chowan River Formations at the Lee Creek Mine in Geology and Paleontology of the Lee Creek Mine, North Carolina II:113-282.

Weisbord, Norman E. 1966. Some late Cenozoic cirripeds from Venezuela and Florida. Bull. Amer. Paleont., vol. 50, no. 225, pp. 1-145, pls. 1-12.

Weisbord, Norman E. 1974. Late Cenozoic Corals of South Florida. Bulletins of American Paleontology vol. 66, no. 285. 544 pp.

Zullo, Victor A., 1992. Revision of the balanid barnacle genus Concavus Newman. Supplement to Journal of Paleontology, v. 66, no. 6, pt. II.

Zullo, Victor A. and Portell, Roger W. 1993. Paleobiogeography of the Late Cenozoic Barnacle Fauna of Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

Paleoecology

Allmon, Warren D. 1992. Whence Southern Florida’s Plio-Pleistocene shell beds? Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Allmon, Warren D; Rosenberg, Gary; Portell, Roger W.; and Schindler, Kevin S. 1993. Diversity of Atlantic Coastal Plain Mollusks since the Pliocene. Science, vol. 260:1626-1629.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Petuch, Edward J. 2007. The Geology of the Everglades and Adjacent Areas. CRC Press.

Biostratigraphy

Dubar, J.R. and J.R. Soliday. 1963. Stratigraphy of the Neogene Deposits of the Lower Neuse Estuary, North Carolina. Southeastern Geology 4(4):213-233.

Ward, Lauck W. 1992. Tertiary Molluscan Assemblages from the Salisbury Embayment of Virginia. Virginia Journal of Science, Volume 43, no. 1B.

Ward, Lauck W. 2008. Synthesis of Paleontological and Stratigraphic Investigations at the Lee Creek Mine, Aurora, NC (1958-2007) in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virginia Museum of Natural History Special Publication No. 14.

Systematics

Bouchet, P., Yu. I. Kantor, A.Sysoev and N. Puillandre. 2011. New Operational Classification of the Conoidea (Gastropoda). Journal of Molluscan Studies (2011) 77: 273–308.

Hulbert, Richard C. (ed.). 2001. The Fossils Vertebrates of Florida. University Press of Florida.

Turgeon, D.D. et al. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. Second edition. American Fisheries Society Special Publication. No. 26. 526 pp.

MikeR

The Caloosahatchee Marl

In 1886 a young adventurer scientist by the name of Angelo Heilprin (1853-1907) made his first expedition of many in a short but event filled career. He would later ascend Ixtaccihuatl and Popcatepetl volcanoes in Mexico and was the first scientist to arrive at the city of Saint-Pierre, Martinique after the eruption of Montagne Pelee killed 30,000 in 1902 and would return four years later descended into its crater. He embarked with Robert Peary on his expedition to Greenland in 1891 and led the Peary relief expedition the following year. He was a professor and later curator of the Academy of Natural Sciences in Philadelphia, a painter who exhibited in both the Pennsylvania and Boston academies of fine art, held a chair at Yale and was a founding member of the American Alpine Society. His exploration of the Florida west coast and Lake Okeechobee seems rather mundane today. A drive east along Florida State Highway 20 from Port Charlotte to Labelle by the farms and developments which parallel the channeled Caloosahatchee River and levied Lake Okeechobee belie the wilderness that existed a mere 125 years ago. In the late 19th century the large inland lake was not unknown but earlier attempts to reach it by the Caloosahatchee River ended in impenetrable swamp. Working under the auspices of the Academy of Natural Sciences and the Wagner Free Institute of Science, Heilprin set sail from Cedar Keys, Florida aboard the schooner Rambler with two wealthy Philadelphia backers Joseph Wilcox and Charles Brock, the captain Frank Strobhar and Moses Natteal the cook to access the lake by the Caloosahatchee River by way of the newly dredged canal of the Florida Land Improvement Company. Heilprin’s narrative of the expedition would result in Volume I of the Transactions of the Wagner Free Institute of Philadelphia. At times it reads more like Conrad’s Heart of Darkness than that of the first serious scientific study of the geology and wildlife of the South Florida interior. The descriptions of today’s St. Petersburg coastline and the panther inhabited interior seem alien compared to the present and his commentary on the over-harvesting of alligator in the Florida interior prescient. Of all the observations that he reported upon, none were as unexpected as the evidence of an ancient sea found within the canal banks connecting Lake Okeechobee. Heilprin at once recognized species in this shell bed different from those that presently inhabit Floridian waters and devoted a large portion of his publication on description of the fossils in the soft crumbly limestone that he named the Caloosahatchee Marl (fig. 1).

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Figure 1. Endemic gastropods from the Caloosahatchee Formation. All are from Hendry County, Florida.

The fossil fauna found in what we now call the Caloosahatchee Formation succeed that of the underlying Pinecrest Beds. The regression that occurred after the final Pinecrest phase left the Everglades basin well above sea level for several hundred thousand years before being flooded once more by a global warm spell in the Early Pleistocene. The shallow inland lagoon that formed was superheated resulting in a truly tropical environment much different than that found along the Atlantic coast of the time. Although slightly less diverse than the preceding Pinecrest which preserved multiple facies, the Caloosahatchee was considerably richer than the contemporary North Florida Nashua, the Waccamaw of the Carolinas and the northernmost James City deposits. In the Caloosahatchee Formation along with mollusks are found vertebrates, echinoids (fig. 2) and corals. The presence of a large coral component in the white limey marl is typical of the Caloosahatchee. The coral fauna itself is less diverse than that of the corresponding Caribbean however much more abundant in individuals than that of the Pinecrest and consists of Upper Pliocene survivors, Caribbean immigrants and endemics (fig.3).

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Figure 2. Echinoids from the Caloosahatchee Formation. Specimens in the middle and on the right have spines preserved.

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Figure 3. Corals from the Caloosahatchee Formation. From left to right Dichocoenia caloosahatcheensis Weisbord, 1974, Hendry County, Florida; Dichocoenia eminens Weisbord, 1974, Hendry County, Florida; Placocyathus sp., Collier County, Florida.

In previous posts I have included site pictures however most of my Caloosahatchee collecting has been from FDOT spoil piles outside of the quarries from which the material was mined. Only once have I had the opportunity to collect from a Caloosahatchee quarry and that was the Cochran shell pit in the mid 1980s when I was not concerned so much with photography. It is from that site in which most of my larger Caloosahatchee shells were derived. As with my previous posts, I have included the complete specimen list in my collection from the Caloosahatchee Marl.

Caloosahatchee species list 122613.pdf

REFERENCES

Allmon, Warren D; Rosenberg, Gary; Portell, Roger W.; and Schindler, Kevin S. 1993. Diversity of Atlantic Coastal Plain Mollusks since the Pliocene. Science, vol. 260:1626-1629.

Campbell, Lyle. 1975. Check List of Marine Pliocene Mollusks of Eastern North America in Plio-Pleistocene Faunas of the Central Carolina Coastal Plain. Geologic Notes (South Carolina Division of Geology) Vol. 19, No. 3.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Dall W.H. 1890-1903. Contributions to the Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchie River, Part I: Pulmonate, Opisthobranchiate and Orthodont Gastropods, Transactions of the Wagner Free Institute of Science of Philadelphia 3(1-VI).

Heilprin, Angelo. 1887. Explorations on the west coast of Florida and in the Okeechobee wilderness : with special reference to the geology and zoology of the Floridian peninsula : a narrative of researches undertaken under the auspices of the Wagner Free Institute of Science of Philadelphia. Transactions of the Wagner Free Institute of Science of Philadelphia v. 1.

Hendricks, Jonathan. 2008. The genus Conus (Mollusca: Neogastropoda) in the Plio-Pleistocene of the southeastern United States, Bulletins of American Paleontology 375.

Olsson, A.A. 1967 (1993 Reprint). Some Tertiary Mollusks from South Florida and the Caribbean, Originally - Bulletins of American Paleontology 54(242), The Paleontological Research Institute Special Publication 19: pages 11-75, 9 plates

Olsson, A.A., and A. Harbison. 1953 (1990 Reprint). Pliocene Mollusca of Southern Florida with Special Reference to Those from North Saint Petersburg, with special chapters on Turridae by W.G. Fargo and Vitinellidae and Fresh-water Mollusks by H.A. Pilsbry, The Academy of Natural Sciences of Philadelphia Monographs 8, The Shell Museum and Educational Foundation, 457 pages, 65 plates

Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217): pages 509-574, plates 77-83

Olsson, A.A., and R.E. Petit. 1968 (1993 Reprint). Notes on Siphocypraea, Originally - Special Publication 9, The Paleontological Research Institute Special Publication 19: pages 77-88.

Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Petuch, Edward J. 2007. The Geology of the Everglades and Adjacent Areas. CRC Press.

Portell, Roger W. and Craig W. Oyen. June 2002. Pliocene and Pleistocene Echinoids. Florida Fossil Invertebrates Part 3, 30pp.

Portell, Roger W. and Jeffery G. Agnew. February 2004. Pliocene and Pleistocene Decapod Crustaceans. Florida Fossil Invertebrates Part 4, 29 pp.

Portell, Roger W. and B. Alex Kittle. December 2010. Mollusca, Bermont Formation (Middle Pleistocene). Florida Fossil Invertebrates Part 13, 40 pp.

Weisbord, Norman E. 1974. Late Cenozoic Corals of South Florida. Bulletins of American Paleontology vol. 66, no. 285. 544 pp.

Waller, T.R. 1969. The evolution of the Argopecten gibbus stock (Mollusca: Bivalvia), with emphasis on the Tertiary and Quaternary species of eastern North America. Journal of Paleontology, Memoir 3 (vol. 43, suppl. to No. 5).

Zullo, Victor A. and Portell, Roger W. 1993. Paleobiogeography of the Late Cenozoic Barnacle Fauna of Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

MikeR

James City Formation

In deciding upon a title for this post, my first inclination was to name it “The Fossil Shells of the Lee Creek Mine.” As mollusks are found within the entire 20 million year span of deposits at Lee Creek, that title does not fit into the theme of my recent posts about the Lower Pleistocene of the Southeastern United States. For the vertebrate collectors who once visited this fossil nirvana, the type of mollusk shells indicated the particular layer one was collecting. The presence of massive amount of shell was bad for the bone hunters but of great interest to those who specialize in invertebrates. Anyone who is knowledgeable about LCM’s geology will know that the main shell bed belongs to the Early Pleistocene James City Formation and at one time the LCM deposit was the most accessible James City locality. Named by Dubar and Soliday for deposits along the Neuse River (fig. 1), those exposures are now mostly covered by river front properties whose owners rip-rap the bluffs in the belief that it will delay the erosion that will one day dump their houses into the river.

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Figure 1. First two pictures are from the type locality of the James City Formation, Neuse River, Craven County, North Carolina. Third picture is of shells weathered from a James City deposit (Loc. 1021), mostly Mercenaria campechiensis permagna (Conrad, 1838). Neuse River, Pamlico County, North Carolina.

These beds represent the northernmost exposure of Lower Pleistocene deposits in the Eastern United States and are of the same age as the Waccamaw Formation that I have written about in the past. Although extremely rich in individuals, the diversity is lower than that of the Waccamaw as it was north of the warm water barrier that separated the Upper Pliocene Yorktown from the Duplin Formation further south. The regional succession of faunas however show that the James City was more diverse than the underlying Chowan River Formation which was recovering from the Yorktown extinction, but never to the richness of Zone 2 Yorktown Formation that both the Chowan River and James City overlies. That said the James City Formation still contains beautifully preserved specimens with a number of endemic mollusks not found in either the Waccamaw of the lower Carolinas or the Caloosahatchee Marl of Florida.

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Figure 2. Some gastropods from the James City Formation. A) Heilprinia caloosaensis malcomi Ward & Blackwelder, 1987; 6.8 cm B ) Fasciolaria beaufortensis Ward & Blackwelder, 1987; 9.3 cm C) Trigonostoma elizabethae Olsson & Petit, 1964; 4.0 cm D) Volutifusus obtusa (Emmons, 1858); 12.5 cm. All are from the Lee Creek Mine, Beaufort County, North Carolina.

Attached is the species list from the James City Formation in my collection.

James City species list 110213.pdf

References

Dubar, J.R. and J.R. Soliday. 1963. Stratigraphy of the Neogene Deposits of the Lower Neuse Estuary, North Carolina. Southeastern Geology 4(4):213-233.

Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217):509-574.

Ward L.W. and Blackwelder, B.W. 1987. Late Pliocene and Early Pleistocene Mollusca from the James City and Chowan River Formations at the Lee Creek Mine in Geology and Paleontology of the Lee Creek Mine, North Carolina II:113-282.

MikeR

Primary amongst the various indicators that define the Quaternary Period is the cyclic global cooling known as the Ice Ages. Although cyclic glaciation happened throughout the Cenozoic, the shear number of occurrences in the Pleistocene are notable with no less than 13 different events. As would be expected, the constant rise and fall of sea level controlled by the amount of water caught up by glaciers and the resulting changes in temperature and aridity would play havoc with biological communities, especially so with marine environments. By the end of the Pliocene, much of the molluscan fauna of the Upper Mid-Atlantic waters had already become extinct. The warmer Floridian waters weathered these climatic changes a little better, but the extinction rates for the Tamiami mollusks were still high. The old eastern United States embayments in which the Upper Pliocene Yorktown/Duplin/Jackson Bluff/Tamiami communities existed lay above sea level for several hundreds of thousands of years before the melting glaciers of the Early Pleistocene re-flooded the basins once more.

In my posts about the Upper Pliocene, I have made frequent references to stage names such as Piacenzian and Calabrian. These are chronostratigraphic units established by the International Commission on Stratigraphy (ICS) which allows geologists to temporally align deposits found around the world. For instance the Pinecrest Beds of Florida, the Zone 2 Yorktown Formation of Virginia, the Imperial Formation of California, and the Gurabo Formation of the Dominican Republic are all of the same age as the namesake deposits in Piacenza, Italy. Traditionally the Early Pleistocene Calabrian Stage followed the Piacenzian however the Gelasian Stage was established in 1998 based upon specific magnetostratigraphic boundaries and nanoplankton extinctions (Rio et. al., 1998). It marks the lowest stage of the Pleistocene overlying the Upper Pliocene Piacenzian and underlying the Middle Pleistocene Calabrian. Those formations deposited between 1.8 and 2.5 mya which in previous posts I attributed to the Calabarian (Caloosahatchee, Nashua, Waccamaw, and James City) now lie within the Gelasian Stage.

In the next few posts, I will be describing the Gelasian deposits found along the Atlantic and Gulf coastal plains. One of these, the Waccamaw Formation, I have already discussed (http://www.thefossilforum.com/index.php?/blog/101/entry-105-waccamaw-formation/). Those who are fortunate enough to have collected from the Waccamaw know of the incredibly rich shell beds containing not only mollusks but echinoids as well (fig. 1). Many of the Duplin mollusks became extinct prior to the end of the Pliocene however a survey of gastropods in the Lower Pleistocene Waccamaw shows an almost identical number of species. A principle of molluscan biology is that the warmer the water the higher is gastropod diversity. Therefore a return to the same abundance of gastropods early in the Pleistocene demonstrates that high extinction rates were accompanied by a high evolutionary origination rate probably due to the return of subtropical conditions in the Mid-Atlantic (Allmon et. al., 1993).

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Figure 1. Echinoids from the Lower Pleistocene Waccamaw Formation. From left to right: Arbacia waccamaw Cooke, 1941; Arbacia rivuli Cooke, 1941; Rhyncholampas sabistonensis (Kellum, 1926); Leodia caroliniana (Ravenel, 1841); Mellita aclinensis Kier, 1963. M. aclinensis is from Columbus County, North Carolina. All others are from Horry County, South Carolina.

In my earlier posts I attached species lists containing only mollusks of a particular location, however I have to admit I liked the look of the total fauna list that I produced for the Piacenzian. As a result I am now posting the total fauna list in my collection from the Waccamaw Formation. Of course it is dominated by mollusks and if a comparison is made between this and my other Waccamaw lists, one will see some new species as well as some that are missing. This is attributed to refinements in my identifications in which the missing are identified as a variant or a different species altogether. Other than mollusks and echinoids other fossil groups are not well represented. Although common at some localities, only a single coral species, Septastrea crassa occurs in the Waccamaw. Vertebrates are also not very common. I have found only two sharks teeth in the Waccamaw and one Hemipristis serra might be redeposited as I could find only meager references as to its survival past the Pliocene.

Waccamaw species list_Reagin.pdf

References

Allmon, Warren D; Rosenberg, Gary; Portell, Roger W.; and Schindler, Kevin S. 1993. Diversity of Atlantic Coastal Plain Mollusks since the Pliocene. Science, vol. 260:1626-1629.

Rio, Domenico; Sprovieri, Rodolfo; Castradori, Davide; and Di Stefano, Enrico; 1998. The Gelasian Stage (Upper Pliocene): A new unit of the global standard chronostratigraphic scale. Episodes, 21(2): 82-87.

MikeR

I made my first trip to France in 1997 while working as a bench scientist in a R&D group at a small biotech company. At that time I was performing research in DNA polymerases from thermophilic bacteria found in geysers and deep ocean vents for the use in DNA sequencing when I had the opportunity to attend an international scientific conference; Thermophiles 1997 in Brest, France. A scientific meeting on the European continent with exquisitely catered lunches served with wine, bike excursions on the Atlantic Isles off the Brittany coast and Celtic music after party were much in contrast with the expense conscious events that I was accustom to in the States. In addition to expanding my knowledge in my life chosen field, this trip gave me an opportunity to collect the famous Eocene fossil shell beds of the Paris Basin (more on that at a later date) as well as a week of free room and board in Paris due to the generosity of a friend of a friend. One of the many sites in Paris on my visitation list was the Galerie de Paléontologie et d’Anatomie Comparée (Gallery of Paleontology and Comparative Anatomy) of the National Museum of Natural History. I remember well on that overcast day, arriving on the metro to the Jardin du Plantes where the museum resides to find the gallery closed for the first time in 100 years due to renovations. Dejected, I did not know if I would ever again have the opportunity to mark this excellent museum off my bucket list. Fortune however, sometimes smiles as almost a decade and a half later on my return from a business trip to the Middle East in March I managed a fortuitous ten hour layover in Paris. Not to be denied this time, I dropped my bag off in the airport upon my arrival from Riyadh and hopped the train over to the Cathedral of Notre Dame and the short walk to the museum.

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Views of Lamark's statue at the entrance to the botanical gardens and the exterior of the gallery.

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A display of primitive plants outside of the museum. Right: Araucaria araucana, aka the monkey puzzle tree is of the same genus as the Triassic aged stone logs from the Petrified Forest National monument in Arizona. On the left is another living fossil , the Wollemi Pine Wollemia nobilis. Once thought extinct in the Cretaceous, a small grove was discovered in 1994 in Australia’s Wollemi National Park. Through secrecy of the specific location and seed distribution amongst horticulturists and botanists, it is hoped that this species will survive an accidental plant virus which threatens its original site.

Founded in 1898 the gallery houses an incredible collection of modern and fossil vertebrate skeletons as well as fossil invertebrates. Great 19th century French naturalists are held in esteem here as their busts adorn the exterior walls of the building. Geroges Cuvier’s bust is displayed alongside that of Lamarck both bitter rivals in life who likenesses are now doomed to spend eternity besides each other. Cuvier was a bit of a 19th century Sheldon Cooper, a prickly boy wonder dismissive of his contemporaries, who became the most pre-eminent anatomist of his time and one of the first naturalists to recognize the concept of extinction. He believed that taxonomic turnover at different geological eras was due to great catastrophes. Although much of his thought and scientific reasoning was before his time, he believed in the fixity of species not on theological reasons but due to the lack of evidence otherwise. This clashed with the theories of Lamarck who postulated an early concept of evolution through acquired characteristics in which anatomical traits through excessive use could be transferred by a parent. Although Lamarck’s theory is discounted, it is still noted in most college level biology texts as early evolutionary thought and decades prior to Darwin’s principle of natural selection . Unfortunately for Lamarck, he preceded Cuvier in death. As a result, Cuvier had the honor of writing Lamarck’s eulogy which was so demeaning and condescending that it was never published (http://www.victorianweb.org/science/science_texts/cuvier/cuvier_on_lamarck.htm).

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The bust of Jean Baptist Pierre Antoine de Monet aka Lamarck. Lamarck first made his mark in botany before turning himself to the identification of fossil shells from the French Eocene and Miocene sands. Some of the many fossils shells in my collection described by Lamarck from left to right include Campanile gianteum (Lamarck, 1822), Middle Eocene (Lutetian), Damery, Marne, FRANCE; Mitra elongata (Lamarck, 1803), Middle Eocene (Lutetian), Villiers-St. Fredric, Yvelines, FRANCE; Eutritonium nodularium (Lamrack, 1803), Middle Eocene (Lutetian), Villiers-St. Fredric, Yvelines, FRANCE; Delphinula lima Lamarck, 1824, Upper Eocene (Bartonian), LaGuepelle, Val d'Oise, FRANCE; Volutilithes ficulina (Lamarck, 1811), Middle Miocene (Helvetian), Lale, TURKEY.

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The bust of Alcide Charles Victor Marie Dessalines d’Orbigny. A disciple of Cuvier, he was a natural historian who not only named many different recent and fossil worldwide species but also explored the South American coast around the same time as Charles Darwin. A few of the fossils in my collection named by d’Orbigny include from left to right Anomia simplex d'Orbigny, 1845, Upper Pliocene, Jackson Bluff Formation, Leon County, Florida; Tritonidea subandrei (d’Orbigny, 1850), Upper Eocene (Bartonian), LaGuepelle, Val d'Oise, FRANCE; Natica noae d’Orbigny, 1850, Upper Eocene (Bartonian), LaGuepelle, Val d'Oise, FRANCE; Ampullina parisiensis (d’Orbigny, 1850), Upper Eocene (Bartonian), Le Chapelle-en-Serval, Oise, FRANCE; Urosalpinx subrusticus (d’Orbigny, 1852), Upper Miocene, St. Marys Formation, Windmill Point Member, St. Marys County, Maryland.

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The bust of Henri Milne-Edwards. The 27th child of an English-Jamaican planter and French mother was also a student of Cuvier. His claim to fame was two giant monographs one on fossil crabs and the other on fossil corals including many from the United States. From left to right Diploctenium subcirculare Milne-Edwards & Haime, 1860, Upper Cretaceous (Santonian), La Noguera, Catalonia, SPAIN; Leptoria konicki Milne-Edwards & Haime, 1860, Upper Cretaceous (Maastrichtian), Pallas Jussa, Catalonia, SPAIN; Balanophyllia haleana (Milne-Edwards & Haime, 1848), Lower Eocene, Bashi Formation, Lauderdale County, Mississippi; Balanophyllia desmophyllum Milne-Edwards & Haime, 1848, Middle Eocene, Tallahata Formation, Choctaw County, Alabama; Discotrochus orbianianus Milne-Edwards & Haime, 1848, Middle Eocene, Stone City Formation, Burelson County, Texas.

The first floor of the gallery houses skeletons of modern vertebrates including those from the smallest birds to large whales, many studied and mounted by Cuvier himself. Amongst the numerous mounts were remains from extinct animals such as the Dodo and Steller’s Sea Cow. A display of deformed elephant skulls lend credence to the theory that the Cyclops of ancient Greek mythology could have originated from the discovery on Aegean islands of the remains of pygmy elephants which had been hunted to extinction by earlier human inhabitants.

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Views of the first floor modern vertebrate gallery. A bust of Cuvier stands vigil in front of the whales.

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A display of deformed elephant skulls and the skeleton of Steller’s sea cow, the largest member of Sirenia which was once abundant in the North Pacific. Within 27 years of its discovery in 1741, it was hunted to extinction for food by Russian whalers.

The second floor contains fossil vertebrates of all eras. Noteworthy amongst the specimens is the skull of the first documented mosasaur, Mosasaurus hoffmani, correctly described by Cuvier as an extinct marine creature related to monitor lizards. Found in a Dutch chalk quarry in Maastricht in 1764, the fossil was already famous when it was stolen from a local museum by Napoleon’s troops in 1794. Also fascinating is the skeleton of Aepyornis maximus and its eggs. The elephant bird, so named because of its size, survived to modern times in Madagascar only to be consumed for food by later human inhabitants and rumored to have still existed when the first western visitors arrived in the 16th century.

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Views of the second floor fossil vertebrate gallery.

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Skeleton of the Elephant Bird and its excellently preserved eggs from Madagascar with my size 10 ½ foot for comparison and the first described Mosasaur

The third gallery on the uppermost floor contains fossil invertebrates including the largest display of ammonites that I have ever seen. In lesser numbers (sadly for me) were fossils from the famous French Eocene and Miocene shell beds recognized by geological stage names such as Lutetian, Aquitanian, and Helvetian.

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Echinoids, ammonites and shells on the third floor fossil invertebrate gallery.

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Skeleton of Raphus cucullatus. This is one of my favorite pictures as my reflection on the Dodo’s glass coffin is a rumination on the fleeting existence of species. For an excellent read on elephant birds, dodos, pygmy elephants, island biogeography and extinction check out The Song of the Dodo by David Quammen.

MikeR

The End Of My Pliocene Project

When I began this blog late in 2010, my intention was to report on recent field trips however, with the exception of one excursion each into the Upper Miocene, Lower Pliocene and the Calabrian Pleistocene, all of my posts have concentrated on the Upper Pliocene of the US Atlantic and Gulf coastal plains. I already had an extensive collection of Florida Upper Pliocene invertebrates that I had collected while a resident of the state in the late 80s and early 90s. The fossils from these beds are contemporaneous with the Zone 2 Yorktown beds of Virginia and North Carolina that I began collecting in the early 2000s, the Duplin Formation that I collected in 2010 and several trips to Jackson Bluff localities in the Florida panhandle in 2011. These more recent collecting endeavors required a reassessment of the identification of my Florida collection due to a better recognition on my part of modern thoughts on speciation and from working with paleontologists who research these deposits. Also I began rejecting non-peer reviewed books and guides geared toward amateurs which exhibited sloppy and unsubstantiated research. In an effort to free display space I began cross-referencing species from different formations to compile at least what I believe is very accurate species identifications and to place the best example of each species regardless of formation within my display cabinets (fig. 1 & 2).

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Figure 1. Upper Pliocene (Piacenzian) Bivalvia Eastern United States.

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Figure 2. Upper Pliocene (Piacenzian) Gastropoda Eastern United States.

The attached species list represents the completion of my Pliocene project. Unlike my previous lists which concentrated on the mollusks from particular sites and formations, the 16 page document below is a compilation of all Eastern United States Piacenzian fossils in my collection both vertebrate and invertebrate. The ability to observe different species geographically has led to changes that can be seen if comparing mollusks in the list below to those noted from my previous posts. I have eliminated species which were obviously the same but named differently based upon the regional description of the molluscan fauna by earlier research. The list is not meant to be comprehensive of these deposits, but more of a guide of what can be found. Although my collection is strong in Sarasota area Pinecrest, Jackson Bluff Formation and Zone 2 Yorktown, it is very weak in Pinecrest fauna from the coral reef facies near Miami and the Kissimmee River area, weak in the Duplin Formation (only two localities sampled), and almost absent other than a few trades from early Piacenzian faunas from the Raysor and Goose Creek Formations of the Carolinas. For a more extensive list of species from this period of time I would refer those interested in mollusks to Campbell (1993) and for Florida vertebrates to Hulbert (2001).

Piacenzian Fauna List_Reagin.pdf

The systematics of the specimens listed are by those fields that I find the most useful in query searches within my Access database and for the most part are as follows: Phylum, Class, Order, Family, Genus, Species, and Subspecies. In stating the distribution of each species, only the formation is noted not the individual members of the Yorktown and Tamiami Formations. Abbreviations used are Yorktown (Y), Duplin (D), Jackson Bluff (J), Tamiami (T) Chowan River (C ), Goose Creek (G) and Raysor (R ). For those taxa which are near to another cf. (similar to) was used. Less specific affinity (aff.) as well as species undetermined (sp.) are designated.

The reasoning behind classification I used is addressed in the notes section below.

NOTES

Algae. A single species of calcareous algae was found in the limestone facies (Ochopee) of the Tamiami Formation which could not be identified to genus or species.

Bryozoa. The identification of bryozoa is highly specialized requiring microscopic identification of various feeding structures. Due to a lack of references and interest I identified most as bryozoa species.

Anthozoa. Eleven species of coral were collected; almost all of which are from the Pinecrest. The exception is the ubiquitous Septastrea marylandica which led a commensal lifestyle by growing on hermit crab inhabited gastropod shells. The other coral outside the Pinecrest was Septastrea crassa found near Williamsburg, Virginia which I obtained with a collection of Zone 2 Yorktown fossils in a trade from the 80s. Since I did not collect it personally and have not found this particular species at any of the numerous Zone 2 sites that I have collected over the past decade I have designated it as questionable from the Yorktown (Y?).

Brachiopoda. Only a single Upper Pliocene brachiopod is listed. Discinisca lugrubris is a geologically wide ranging species found from the Lower Miocene to the Upper Pliocene colder water Bed 11 of the Pinecrest Member of the Tamiami Formation and the Jackson Bluff Formation.

Mollusca. Since Piacenzian deposits are known world wide for their shell beds, it stands to reason that mollusks should dominate. The list contains 244 species and subspecies of bivalves, 370 of gastropods and 6 scaphopods. In general, the warmer the water, the higher is gastropod diversity. The list shows that bivalves are wide ranging and less so with gastropods where many more were found only in the warmer water Tamiami Formation. Aragonitic shells do not preserve well in carbonate environments and are often difficult to identify to species. Those shells from the Ochopee Member of the Tamiami Formation that were preserved as internal casts that I felt were probably represented in Pinecrest were not listed separately (i.e. Ficus sp. Internal cast from the Ochopee is probably Ficus jacksonensis from the Pinecrest). I followed the systematics of Turgeon et. al. (1998) which Roger Portell Director, Division of Invertebrate Paleontology of the Florida Museum of Natural History uses for the mollusks in the Florida Paleontology Society publications. This has led to some interesting changes in classification of gastropods within my collection. In a previous post to the forum, I had mentioned that at some point the subgenera of the family Turritellidae had been reclassified to genera. As stated by Turgeon concerning several recent species that were reclassified in this manner “We do not know the source of this reclassification nor have we seen evidence of subsequent acceptance...” therefore I reclassified all genera in Turritellidae back to Turritella with the exception of valid Vermicularia. The most drastic change in classification had to be with members from the families Turridae, Drillidae, and Conidae. I originally classified all turrids in Turridae by older systematics based solely on shell characteristics. I have known for awhile that at some point the family had been split based upon internal structure of the animal itself and DNA studies. What I did not know was that some of those species had been reclassified as Conidae. Turgeon noted that the study was controversial but was supported by anatomical and radular data and also stated that the affected subfamilies would be better suited in their own family. It was difficult for me to classify genera Glyptostoma and Cythara as Conidae, but I did so since I committed to using Turgeon.

Cirripedia. Barnacles were more diverse in the Eastern US Upper Pliocene than today but much like bryozoa their specific identification is difficult. Factors for species id include the tubular structure of the outer wall and the internal plates that protect the animal. I feel that most of my identifications are correct however some are based upon morphological features of the outer shell and geographical range and thus might not be accurate.

Decapoda. Crabs are a common component of shell beds, however due to the formation of the beds by winnowing, crabs are rarely preserved intact. The majority of crab finds are as isolated legs, claws, and occasional carapaces. Very little study has been made of Pliocene crabs, but most notable are publications by Rathbun (1935) who identified a wide geographical range of species and those of Florida by Portell and coauthors (2002, 2004). The crabs of the Yorktown Formation are not characterized and in many cases at generic level I used similar to reference (Cf.) which like Cirripedia does not follow proper identification rules.

Echinoids. Much like crabs, disarticulated echinoid remains can be common in shell beds. In limestone however, because of their calcitic tests and gentle conditions in carbonate environments, echinoids can be preserved intact. I have not collected in the Raysor and Goose Creek Formations but I did receive echinoids from these deposits in trades from the 90s. At one point both of these units were considered members of the Duplin Formation. This has led to designation in the list (D/R) meaning that the original label listed Duplin Formation but due to the attached calcareous matrix, I believe that the specimens are from the Raysor.

Vertebrates. Those collectors who have been fortunate to collect at the PCS/Lee Creek Mine are well aware of the rich vertebrate fauna found in the Yorktown Formation. The Yorktown however is divided into two different units—Zone 1 Lower Pliocene (Zanclean) and Zone 2 Upper Pliocene (Piacenzian). One of the distinguish features of these two zones is the richness of vertebrates in Zone 1 compared to their very sparse nature in Zone 2. Vertebrates during this interval are only common in Pinecrest Beds 4 and 11 and a bone layer in Bed 3 consisting of a mass die off of cormorants during a red tide which I never collected. Marine vertebrates can also be found within the Jackson Bluff Formation but not as plentiful as the previously described beds. Redeposited vertebrate remains are found in the Upper Pliocene of the Carolinas and Virginia and are not included in my list. These include teeth of the Cretaceous sharks Squalicorax kaupi and Scapanorhynchus texanus that I have found in the Duplin Formation and vertebrates from the lag deposit found at the contact between the Upper Cretaceous Black Creek Group and Zone 2 Yorktown Formation at my locality 1012 which probably represented concentrated bones and teeth from the Lower Pliocene and Upper Miocene. Upper Pliocene vertebrate remains besides bony fish, shark and ray in my collection include one marine turtle, one land tortoise, a capybara, a walrus, and a dugong. I classified large whale remains as Mysticeti and smaller remains as Odontoceti dolphin although there could be crossover.

REFERENCES

Numerous references were used and I have them listed according to those for identification or taxonomy and those that I used in writing about the geology or ecology of the deposits described within my blog. In addition to the below publications, I found Greta Polites Fossil Muricidae Website (http://glpolites.us/murex/index.htm) to be invaluable in eliminating synonymous species. My only deviation from her list was with Ecphora which I only recognized two species, E. quadricostata and bradlyae.

Identification

Campbell, Lyle. 1975. Check List of Marine Pliocene Mollusks of Eastern North America in Plio-Pleistocene Faunas of the Central Carolina Coastal Plain. Geologic Notes (South Carolina Division of Geology) Vol. 19, No. 3.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Dall W.H. 1890-1903. Contributions to the Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchie River, Part I: Pulmonate, Opisthobranchiate and Orthodont Gastropods, Transactions of the Wagner Free Institute of Science of Philadelphia 3(1-VI).

Gardner, J. A. 1944. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 1. Pelecypoda, United States Geological Survey Professional Paper 199-A: iv, pages 1-178, plates 1-23

Gardner, J. A. 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 2. Scaphopoda and Gastropoda, United States Geological Survey Professional Paper 199-B: iv, pages 179-310, plates 24-38, [iii]

Gardner, J. A. and T.H. Aldrich. 1919. Mollusca from the Upper Miocene of South Carolina: with Descriptions of New Species. Proceedings of the Academy of Natural Sciences of Philadelphia 71: pages 17-53.

Gibson, Thomas G. 1987. Miocene and Pliocene Pectinidae (Bivalvia) from the Lee Creek Mine and Adjacent Areas in Geology and Paleontology of the Lee Creek Mine, North Carolina, II. Smithsonian Contributions to Paleobiology No. 61.

Hendricks, Jonathan. 2008. The genus Conus (Mollusca: Neogastropoda) in the Plio-Pleistocene of the southeastern United States, Bulletins of American Paleontology 375.

Kohno, Naoki and Ray, Clayton E. 2008. Pliocene Walruses from the Yorktown Formation of Virginia and North Carolina, and a Systematic Revision of the North Atlantic Pliocene Walruses in The Geology and

Paleontology of the Lee Creek Mine, North Carolina, IV. Virginia Museum of Natural History Special Publication No. 14.

Mansfield, W.C. 1930. Miocene Gastropods and Scaphopods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 3, 189 pages.

Mansfield, W.C. 1931. Some tertiary mollusks from southern Florida. Proceedings of the United States National Museum, v. 79.

Mansfield, W.C. 1931. Pliocene Fossils from Limestone in Southern Florida in Shorter Contributions to General Geology, USGS Professional Paper 170, 11 pages.

Mansfield, W.C. 1932. Miocene Pelecypods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 8, 233 pages.

Mansfield, W.C. 1936. Stratigraphic Significance of Miocene, Pliocene, and Pleistocene Pectinidae in the Southeastern United States, Journal of Paleontology, Vol 10, No. 3, 24 pages.

Mansfield, W.C. 1939. Notes on the Upper Tertiary and Pleistocene Mollusks of Peninsular Florida, Florida Geological Survey Bulletin 18, 128 pages.

Mansfield, W.C., 1943 [1944]. Stratigraphy of the Miocene of Virginia and the Miocene and Pliocene of North Carolina in Gardner, Julia ed. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina. USGS Professional Paper 199A, p. 1-19.

Hollister, S.C. 1971. New Vasum Species of the Subgenus Hystrivasum. Bulletins of American Paleontology 262.

Olsson, A.A. 1967 (1993 Reprint). Some Tertiary Mollusks from South Florida and the Caribbean, Originally - Bulletins of American Paleontology 54(242), The Paleontological Research Institute Special Publication 19: pages 11-75, 9 plates

Olsson, A.A., and A. Harbison. 1953 (1990 Reprint). Pliocene Mollusca of Southern Florida with Special Reference to Those from North Saint Petersburg, with special chapters on Turridae by W.G. Fargo and Vitinellidae and Fresh-water Mollusks by H.A. Pilsbry, The Academy of Natural Sciences of Philadelphia Monographs 8, The Shell Museum and Educational Foundation, 457 pages, 65 plates

Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217): pages 509-574, plates 77-83

Olsson, A.A., and R.E. Petit. 1968 (1993 Reprint). Notes on Siphocypraea, Originally - Special Publication 9, The Paleontological Research Institute Special Publication 19: pages 77-88.

Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.

Portell, Roger W. and Craig W. Oyen. June 2002. Pliocene and Pleistocene Echinoids. Florida Fossil Invertebrates Part 3, 30pp.

Portell, Roger W. and Jeffery G. Agnew. February 2004. Pliocene and Pleistocene Decapod Crustaceans. Florida Fossil Invertebrates Part 4, 29 pp.

Portell, Roger W. November 2004. Eocene, Oligocene and Miocene Decapod Crustaceans. Florida Fossil Invertebrates Part 4, 29 pp.

Portell, Roger W. and B. Alex Kittle. December 2010. Mollusca, Bermont Formation (Middle Pleistocene). Florida Fossil Invertebrates Part 13, 40 pp.

Rathbun, Mary J. 1935. Fossil Crustacea of the Atlantic and Gulf coastal plain. Geological Society of America. Special papers; no. 2.

Tucker, H.I. and Druid Wilson. 1932. Some new or otherwise interesting fossils from the Florida Tertiary. Bulletins of American paleontology; v. 18: no. 65.

Tucker, H.I. and Druid Wilson. 1933. A second contribution to the Neogene paleontology of South Florida. Bulletins of American paleontology; v. 18: no. 66.

Tuomey, M., and F.S. Holmes. 1855-1856 (1974 Reprint). Pleiocene Fossils of South-Carolina: Containing Descriptions and Figures of the Polyparia, Echinodermata and Mollusca, Original pages 1-30 and plates 1-12 published in 1855, Original pages 31-152 and plates 13-30 published in 1856, The Paleontological Research Institution Special Publication 12: xvi, 152 pages, 30 plates, [addendum]

Ward L.W. and Blackwelder, B.W. 1975. Chesapecten, a New “Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. USGS Professional Paper 861.

Whitmore, Frank C. Jr and Kaltenbach, James A. 2008. Neogene Cetacea of the Lee Creek Phosphate Mine, North Carolina in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virginia Museum of Natural History Special Publication No. 14.

Weisbord, Norman E. 1966. Some late Cenozoic cirripeds from Venezuela and Florida. Bull. Amer. Paleont., vol. 50, no. 225, pp. 1-145, pls. 1-12.

Weisbord, Norman E. 1974. Late Cenozoic Corals of South Florida. Bulletins of American Paleontology vol. 66, no. 285. 544 pp.

Zullo, Victor A., 1992. Revision of the balanid barnacle genus Concavus Newman. Supplement to Journal of Paleontology, v. 66, no. 6, pt. II.

Zullo, Victor A. and Portell, Roger W. 1993. Paleobiogeography of the Late Cenozoic Barnacle Fauna of Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

Paleoecology

Allmon, Warren D. 1992. Whence Southern Florida’s Plio-Pleistocene shell beds? Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Allmon, Warren D; Rosenberg, Gary; Portell, Roger W.; and Schindler, Kevin S. 1993. Diversity of Atlantic Coastal Plain Mollusks since the Pliocene. Science, vol. 260:1626-1629.

Allmon, Warren D; Spizuco, Mathew P. and Jones, Douglas S. 1995. Taphonomy and paleoenvironment of two turritellid-gastropod-rich beds, Pliocene of Florida. Lethaia, vol. 28:75-83.

Allmon, Warren D; Emslie, Steven D.; Jones, Douglas S.; and Morgan, Gary S. 1996. Late Neogene Oceanographic change along Florida’s West Coast: Evidence and mechanisms. The Journal of Geology, vol. 104:143-162.

Christie, Max. 2009. Ecological Interactions Across a Plio-Pleistocene Interval of Faunal Turnover: Naticid Cannibalism North and South of Cape Hatteras, North Carolina. Departmental Honors in Interdisciplinary

Studies Thesis, The College of William and Mary.

Geary, Dana H. and Allmon, Warren D. 1990. Biological and Physical Contributions to the Accumulation of Strombid Gastropods in a Pliocene Shell Bed. Palaios vol. 5:259-272.

Jones, Douglas S and Allmon, Warren D. 1999. Pliocene marine temperatures on the West Coast of Florida: Estimates from mollusk shell stable isotopes In J.H. Wrenn, J.-P. Suc, and S.A.G. Leroy, eds., The Pliocene: Time of Change. American Association of Stratigraphic Palynologists Foundation, Dallas, Texas, pp. 241-250.

Molnar, Peter. 2008. Closing of the Central American Seaway and the Ice Age: A critical review. Paleoceanography Volume 21.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Petuch, Edward J. 2007. The Geology of the Everglades and Adjacent Areas. CRC Press.

Schmidt, D. N., 2007. The closure history of the Panama Isthmus: Evidence from isotopes and fossils to models and molecules. In: Williams, M., Haywood, A. M., Gregory, J. F., and Schmidt, D. N. Eds.), Deep

time perspectives on climate change - marrying the signal from computer models and biological proxies. Geological Society of London, London.

Biostratigraphy

Campbell, Kenneth M. 1985. Alum Bluff Liberty County, Florida. Florida Geological Survey Open File Report 9.

Ketcher, Kathleen. 1992. Stratigraphy and Environment of Bed 11 of the "Pinecrest" Beds at Sarasota, Florida in Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey

Special Publication No. 36.

Means, Harley. 2002. Introduction to the Geology of the Upper Apalachicola River Basin in Geologic Exposures Along the Upper Apalachicola River. Southeastern Geological Society Field Trip Guidebook 42.

Missimer, Thomas M. 1992. Stratigraphic relationships of sediment facies within the Tamiami Formation of Southwest Florida: Proposed intraformational correlations. Plio-Pleistocene Stratigraphy and

Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Petuch, E.J. 1982. Notes on the molluscan paleontology of the Pinecrest Beds at Sarasota, Florida with the description of Pyruella, a stratigraphically important new genus: Proceedings of the Academy of Natural

Sciences of Philadelphia, v. 134, p. 12–30.

Ward, Lauck W. 1992. Tertiary Molluscan Assemblages from the Salisbury Embayment of Virginia. Virginia Journal of Science, Volume 43, no. 1B.

Ward, Lauck W. 1992. Diagnostic Mollusks from the APAC Pit, Sarasota, Florida in Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Ward, Lauck W. 1993. Pliocene Stratigraphy and Biostratigraphy, Virginia to Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

Ward, Lauck W. 2008. Synthesis of Paleontological and Stratigraphic Investigations at the Lee Creek Mine, Aurora, NC (1958-2007) in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virginia Museum of Natural History Special Publication No. 14.

Yon, J. William. 1965. Adventures in geology at Jackson Bluff. Florida Geological Survey: Special publication 14.

Systematics

Hulbert, Richard C. (ed.). 2001. The Fossils Vertebrates of Florida. University Press of Florida.

Turgeon, D.D. et al. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. Second edition. American Fisheries Society Special Publication. No. 26. 526 pp.

MikeR

The Black Layer

The end of the Pliocene epoch was a very tumultuous time along the Atlantic and Gulf Coast regions of the United States. With the rise of the Isthmus of Panama, global climate patterns and ocean currents changed. Global change was nothing new and can be observed in the fauna differences between the Lower Pliocene Zone 1 ( Zanclean) and the Upper Pliocene Zone 2 (Piacenzian) Yorktown Formation when a cool temperate fauna was replaced by warm temperate/subtropical species. This local turnover however cannot be well documented on a larger scale because of the lack of widespread well preserved Zanclean molluscan faunas for comparison. On the other hand, environmental disruption due to the continual rise of the Isthmus of Panama can be observed because of excellently preserved shell beds of Upper Pliocene and Lower Pleistocene age along both coasts of North America. Along the Eastern Pacific coast approximately 70% of the Pliocene molluscan fauna survives to today whereas over 70% of that of the Atlantic coast is extinct. Initial extinction between the Zanclean and Piacenzian on the Western Atlantic was attributed to the change from the upwelling of cold water from the ocean depths to the circulation of warm southern waters of the proto-gulf stream. Some additional, as of yet undocumented event occurred at the end of the Piacenzian which cooled or stopped the gulf stream. If not current disruption some other global cooling event occurred which greatly effected the warmer water fauna on the you.S. east coast more profoundly than the already cooler adapted fauna on the Pacific coast. After a single regressive/transgressive cycle the Yorktown and Duplin faunas were almost totally extinct, replaced by the depauparate fauna of the Chowan River Formation (http://www.thefossil...iver-formation/) which is rich in individuals but poor in diversity.

In a previous post I described the incredibly diverse shell beds from the lower beds (7-11) of the Pinecrest Member of the Tamiami Formation that were once exposed in the old APAC quarry near Sarasota, Florida (http://www.thefossil...iami-formation/). A hiatus of perhaps 200 thousand years separated the lower beds from Beds 1-5. The richest of the upper beds, Bed 4, is known as the “Black Layer” for the propensity of the shells contained within to be stained black (fig. 1). This is attributed to a low oxygen, sulfur reducing environment. The fauna in Bed 4 is quite different as well. Whereas the lower beds represented an open marine environment of varying depth, those from the beds 2-5 represent back barrier with brackish/fresh water elements and could be comparable in age to at least the upper member of the Yorktown (Moorehouse) or possibly to the Chowan River Formation. Bed 4 is also known to have one of the richest vertebrate faunas within the Pinecrest. Where the other vertebrate rich layer, Bed 11 contains whales, dolphins, shark and walrus, Bed 4 has a mix of fish and land vertebrates such as giant tortoise.

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Figure 1. Fossil shells from the Bed 4 Black Layer, APAC quarry, Sarasota County, Florida. From left to right, Echinofulgur echinatum helenae Olsson, 1967; Siphocypraea carolinensis floridana (Mansfield, 1930); Pyrazisinus lindae Petuch, 1994; Pyrazisinus scalinus Olsson, 1967; Fulguropsis laevis (Petuch, 1982); Stramonita haemastoma (Linne, 1767).

My wife and I have an agreement. I don’t drag her on fossil collecting trips and she doesn’t force me to go shopping. However when I first began collecting in the 80s, the young Mrs. R would accompany me on my excursions including my first trip to APAC. Perhaps the best find that she ever made was a partial mandible of the capybara Neochoerus dichorplax in Bed 4 sediments (fig. 2). It is an example of a fossil that tells a story specifically that the Isthmus of Panama was emergent and the land mammal exchange between North and South America began in the Late Pliocene.

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Figure 2. Mandible fragment of the Upper Pliocene capybara Neochoerus dichorplax Ahearn & Lance, 1980 Pinecrest Bed 4, Sarasota County, Florida.

The uppermost layer at APAC, Bed 1 contained an entirely new shell fauna from the Lower Pleistocene Caloosahatchee Formation. Lower Pleistocene Calabrian aged deposits range from South Florida north to Virginia and have an interesting story to tell which I will be reporting on shortly.

REFERENCES

Allmon, Warren D. 1992. Whence Southern Florida’s Plio-Pleistocene shell beds? Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Allmon, Warren D; Rosenberg, Gary; Portell, Roger W.; and Schindler , Kevin S. 1993. Diversity of Atlantic Coastal Plain Mollusks since the Pliocene. Science, vol. 260:1626-1629.

Allmon, Warren D; Emslie, Steven D.; Jones, Douglas S.; and Morgan , Gary S. 1996. Late Neogene Oceanographic change along Florida’s West Coast: Evidence and mechanisms. The Journal of Geology, vol. 104:143-162.

MikeR

Chuckatuck

Anyone who has avidly collected fossils for any length of time will have those localities which stand out as their all time favorites based upon the richness or uniqueness of its fossil content. My list includes the APAC mine in Sarasota which I have described in previous posts, the Upper Cretaceous coon Creek deposits of Mississippi and Tennessee, and the subject of this post, The Lone Star Quarry near the town of Chuckatuck, Virginia (fig. 1). This quarry exposed the Moore House Member of the Yorktown Formation and contained one of the richest and most diverse Pliocene shell beds north of Florida. Named by Ward and Blackwelder for now inaccessible exposures on the James River, the Moore House Member represented a time after the Rushmere in which sea levels rapidly dropped and rose within a period of several tens of thousands years. During this rapid regression/transgression cycle, the marine Rushmere fauna was first replaced by brackish water species of the Mogarts Beach member, but when the seas rose once more, the same marine fauna returned. It is theorized that a series of barrier islands existed near Chuckatuck in the Late Pliocene where shells were concentrated by winnowing from currents and storms.

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Figure 1. Location 917 near Chuckatuck, Isle of Wight County, Virginia.

I was fortunate to visit the Chuckatuck pit (locality 917) on multiple occasions between 2003 and 2005. The quarry itself was not as large or deep as those in Florida, more in size to a very large burrow pit. The sediment in the pictures does not appear to be very fossiliferous but belie the actual richness of the pit and the various beds found within. The lowermost layer was a grey silty sand rich in Turritella alticostata and large Busycon incile. Abundant double-valved burrowing clams were common in some parts of the quarry while other locations within contained a marly sand with a diverse gastropod fauna (fig. 2 & 3). Chuckatuck ceased operations shortly after my last visit and unfortunately when work is halted in shell pits along the Mid-Atlantic coastal plain and Florida, the quarries which are often below the water table are rapidly filled with water and overgrown. Like APAC in Sarasota, the Chuckatuck quarry is now a lake. Since quarries in this area exposing these beds have come and gone for the past 100 years, hopefully someday another quarry will open up and be available to the interested public.

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Figure 2. Bivalves from the Moore House Member of the Yorktown Formation, Location 917, Isle of Wight County, Virginia. From left to right: Chesapecten madisonius carolinensis (Conrad, 1873); Carolinapecten eboreus (Conrad, 1833); Chesacardium acutilaqueatum (Conrad, 1839); Crytopleura arcuata (Conrad, 1841).

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Figure 3. Gastropods from the Moore House Member of the Yorktown Formation, Location 917, Isle of Wight County, Virginia. From left to right: Busycon incile (Tuomey & Holmes, 1855); Fusinus exilis burnsii Dall 1890; Ecphora quadracostata (Say, 1824); Pterorytis umbrifer (Conrad, 1832).

Fossil mollusks from Chuckatuck, Location 917 listed in attachments below:

Bivalvia, Loc. 917.pdf

Gastropoda, Loc. 917.pdf

REFERENCES

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Ward, Lauck W. 1992. Tertiary Molluscan Assemblages from the Salisbury Embayment of Virginia. Virginina Journal of Science, Volume 43, no. 1B.

Ward, L.W. and Blackwelder, B.W. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group-Middle Atlantic Coastal Plain. USGS Bulletin 1482-D.

MikeR

Return To The Rushmere

In a previous post (http://www.thefossil...ushmere-member/) I described the Upper Pliocene fossils from the Rushmere Member of the Yorktown Formation in North Carolina and late last year (that is how far I am behind in my cleaning and curating) I returned to two of those Rushmere sites on the Roanoke River (my localities 1011 and 1012) as well as a new site (locality 1019) on the Tar River. On that particular day locality 1012, which is primarily explored for a lag deposit at the base of Rushmere which is rich in vertebrate remains, did not yield many of its treasures. I did however collect many more large bivalves which are present here including nice examples of large and heavy Zone 2 guide fossil, Chesapecten madisonius which could have come from a near shore higher energy environment where the size and weight of the shells could have helped in immobilizing the animal.

Last time, I reported that locality 1011 was unusually rich in gastropods. My return trip to this site did not disappoint and with a longer visit than my last, I was able to do more digging to produce additional examples of volutes, naticids, a few new gastropod species, a fine example of the bivalve, Margarita abrupta with mother of pearl nacre and the largest Ecphora quadricostata that I have ever collected—perfect except for the unfortunate absence of the top few whorls (fig. 1).

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Figure1. Fossil Mollusks from Locality 1011, Roanoke River, Martin County, North Carolina. From left to right: Ptychsalpinx multirugata (Conrad, 1841); Trigonostoma tenerum carolinensis (Emmons, 1858); Margarita abrupta (Conrad, 1832); Ecphora quadricostata (Say, 1824).

This trip was the first time that I have collected on the Tar River. Site 1019 exposed a bluff with a gray and very sandy exposure of the Rushmere rich in bivalves. Chesapecten madisonius were as large as those from locality 1012 however thinner maybe because they were in an open marine environment where the heavy shell was not needed. Also of note were large specimens of Chlamys decemnarius, a Rushmere index fossil. I have collected smaller examples which are typical at other Rushmere sites however these were significantly larger. The one that I collected was 3 inches long. Dr. Lauck “Buck” Ward, professor emeritus at the Virginia Museum of Natural History (who along with Blake Blackwelder, named the Rushmere) led the trip and found a specimen at least 4 inches long remarking that his was one of the largest he has seen. C. decemnarius demonstrates a large degree of variation within the Rushmere (fig. 2) which Thomas Gibson did an excellent job of showing in the second Smithsonian publication of the Lee Creek Mine. Lyle Campbell, in his 1993 Yorktown publication, listed the large ribless form as C. decemnarius virginianus from an earlier description by T.A. Conrad, but noted it as a named variant rather than a subspecies.

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Figure 2. Variation in Chlamys decemnarius. Left: Chlamys decemnarius decemnarius (Conrad, 1834), Locality 770, Meherrin River, Hertford County, North Carolina; Chlamys decemnarius form virginianus (Conrad, 1840), Locality 1019, Tar River, Edgecombe County, North Carolina.

As I reported in my first post about the Rushmere, C. madisonius at site 1011 is unique in having approximately 9-10 ribs whereas those from most other sites have approximately 16 ribs. These specimens with 9 ribs are very similar to the Chesapecten that are found in Bed 11 of the Pinecrest Sand of the Tamiami Formation in Florida (http://www.thefossil...iami-formation/). Campbell called the Rushmere examples Chesapecten madisonus carolinensis based upon Conrad’s description. Buck believes these to be hybrids between 4-8 rib Chesapecten septenarius and 14-16 rib C. madisonius (personal communication). Campbell however reports these at the base of the Rushmere as an intermediate form between Chesapecten jeffersonius from the Zanclean Zone 1 Yorktown and C. madisonius in the Piacenzian Zone 2 Yorktown. This would make sense if not for my observations at the site on the Tar. Here a brown sandy layer is packed with the 9 rib form above the gray sand layer with the 16 rib variant. This would discount Campbell’s interpretation since the material at the top is younger unless a redeposition event occurred such as what could be happening on the James River where Miocene and Pliocene fossil shells from the river bluffs are washed out and possibly redeposited over the recent brackish water fauna. I have noted that at any one site either the 9-10 ribbed form of C. madisonius or the 16 ribbed form dominates. Although I discount his precursor hypothesis, I have decided to use Campbell’s description of that variant as C. madisonius carolinensis (fig.3).

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Figure 3. Variation in Chesapecten madisonius. From left to right: Chesapecten madisonius madisonius (Say, 1824), thick 16 ribbed variant (near shore?) Locality 1012, Roanoke River, Halifax County, North Carolina; Chesapecten madisonius madisonius (Say, 1824),thin 16 ribbed variant (open marine?) lower bed Locality 1019, Tar River, Edgecombe County, North Carolina; Chesapecten madisonius carolinensis (Conrad, 1873), 9-10 ribbed variant upper bed Locality 1019, Tar River, Edgecombe County, North Carolina; Chesapecten madisonius carolinensis (Conrad, 1873), thick 9-10 ribbed variant, Locality 1011, Roanoke River, Martin County, North Carolina.

I have updated my list of fossil mollusks from the above sites as well as added a molluscan list for Locality 1019.

Mollusca Loc 1011.pdf

Mollusca Loc 1012.pdf

Mollusca Loc 1019.pdf

REFERENCES

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Gibson, Thomas G. 1987. Miocene and Pliocene Pectinidae (Bivalvia) from the Lee Creek Mine and Adjacent Areas in Geologoy and Paleontology of the Lee Creek Mine, North Carolina, II. Smithsonian Contributions to Paleobiology No. 61.

Ward, Lauck W. 1992. Tertiary Molluscan Assemblages from the Salisbury Embayment of Virginia. Virginina Journal of Science, Volume 43, no. 1B.

Ward, L.W. and Blackwelder, B.W. 1975. Chesapecten, a New “Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. USGS Professional Paper 861.

Ward, L.W. and Blackwelder, B.W. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group-Middle Atlantic Coastal Plain. USGS Bulletin 1482-D.

MikeR

Jackson Bluff Formation

Many of my posts have mentioned the work of Wendell Cooke Mansfield, one of the giants of early 20th century molluscan paleontology. Among his many accomplishments as a geologist with the United States Geological Survey, Mansfield was the first to publish a biostratigraphical zonation of the Yorktown formation (posthumously in Julia Gardner’s Yorktown publication), describe Pliocene fossils from the sands and limestones which were coming to light in South Florida during the construction of the Tamiami Trail and continued the work of William Healy Dall on the fauna from Miocene and Oligocene limestones near Tampa. I consider his description of the fossil shells found exposed in the creek and river bluffs of the Florida panhandle as his most lasting work. First described as the Choctawhatchee Formation in a series of Florida Geological Survey manuscripts that Mansfield published in the 1930s, he recognized the similarity of the shell bed fauna in the Florida panhandle to that of the Yorktown and Duplin Formations further north. At the time the panhandle faunas were thought to be of Miocene age and divided into the Yolida, Arca, Ecphora, and Cancellaria fauna zones. Subsequent research has revealed that the upper two zones, the Ecphora and Cancellaria are in fact Upper Pliocene and contemporary with the Yorktown, Duplin and Tamiami Formations. The two beds are now combined and called the Jackson Bluff formation for the classic site on the Ochlocknee River. The formation is regionally limited to a three county area in Northern Florida.

I first collected the Jackson Bluff Formation in 1991 by permission to a site managed by the Nature Conservancy. The high bluff on the Apalachicola River exposes both the Lower Miocene Chipola Formation as well as what was once called the Ecphora Zone of the Jackson Bluff Formation. I have since revisited this site (Locality 471) twice, once this year and in 2011. The dark grey sand of the Jackson Bluff Formation here represents a back-bay environment much like that behind the barrier islands along today’s Northern Gulf Coast (Figure 1). This particular site is dominated by the turritellid Eichwaldiella alumensis and the bivalve Mulinia congesta. Other species occur here but are much scarcer in numbers.

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Figure 1. Locality 471, Apalachicola River, Liberty County, Florida. From left to right: Chipola sediments below and Jackson bluff Formation up high; Block of Jackson bluff sediment; Busycon maximum maximum (Conrad, 1839); Ecphora quadricostata (Say, 1824).

New to my collecting endeavors was my Locality 1018 which I visited in 2011 and 2012. This site on the Ochlocknee River once exposed both shell beds of Jackson Bluff. Subsequent weathering and overgrowth has obscured the upper bed but blocks of the lower bed originating from high in the bluff, litter the river shoreline (Figure 2). The same species occur at this site as the previous however, the diversity is much higher as it was deposited in an open marine environment. The sediment here is sticky red clay marl which indicates that that the deposition of this bed was influenced by the ancestral panhandle rivers. Like the red Georgia clay that I am familiar with, this sediment stains everything rust brown and is tough to clean from the fossil shells.

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Figure 2. Locality 1018, Ochlocknee River, Leon County, Florida. From left to right: “Ecphora Zone” of the Jackson Bluff Formation; Block of Jackson bluff sediment; Eichwaldiella alumensis (Mansfield, 1930); Fusinus equalis Emmons, 1858; Spondylus rotundatus Heilprin, 1887.

In several of my earlier posts, I described the environmental histories of the eastern Atlantic Pliocene deposits. Early in the Pliocene, South Florida water temperatures were much cooler than today. By the Late Pliocene ocean temperatures warmed to about the same temperature as in today’s Gulf of Mexico possibly due to the beginning of the permanent emergence of the Isthmus of Panama and the formation of the gulfstream. In the panhandle region of Florida conditions were much different as there was not as much of an effect from the proto-gulf stream. This is evident by closer similarities in the Jackson Bluff fauna to the Mid-Atlantic Yorktown fauna than to the Floridian Pinecrest although the Jackson Bluff does share species from both.

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Figure 3. Endemic or rarely found elsewhere mollusks from the Jackson Bluff Formation. From left to right: Anadara aresta (Dall, 1898) Loc. 471; Busycotypus aepynotum (Dall, 1890) Loc. 471; Busycon maximum tudiculatum (Dall, 1890) Loc. 1018; Fusinus dalli Mansfield, 1930 Loc. 471.

When Mansfield first described the Ecphora zone fauna he recognized slight differences between species of the Jackson Bluff and the Yorktown. As a result, he named many new subspecies of existing Yorktown mollusks. In his 1975 and 1993 works, Lyle Campbell, whose publications I follow extensively, synonymized many of the species and subspecies of the Jackson Bluff with those of the Yorktown. Although I agree with most of his assessments some of the species differences are so consistent and isolated to the Jackson Bluff Formation, that I have kept some Mansfield’s original identifications (Figure 3). The difficulties that I had in identifying the Jackson Bluff fauna are demonstrated in my efforts to name Cancellaria depressa. In 1856 Tuomey and Holmes identified Cancellaria depressa from the Duplin Formation of North Carolina. In 1919 Aldrich and Gardner described Cancellaria tabulata also from the Duplin; similar to C. depressa but with a lesser amount of both spiral and axial sculpture. Mansfield figured Cancellaria tabulata from the Ecphora Zone in 1930 although it appeared identical to C. depressa figured by Tuomey and Holmes. I have a species of Cancellaria in my collection from the Pinecrest of South Florida that strongly resembles Gardner and Aldrich’s C. tabulata; however Campbell synonymized it to C. depressa in 1993. In his 1994 Atlas, Petuch who defenestrates traditional systematics by elevating every subgenus to genus and every subspecies to species without explanation, even agreed with Campbell. In the same publication, Petuch figured from the Pinecrest, Cancellaria plagiostoma bearing a strong resemblance to Aldrich and Gardner’s C. tabulata. Petuch’s photo of C. plagiostoma however, does not resemble the same species described by Campbell, a small (6 mm) shell found only at a single Yorktown location on the James River in Virginia. At first I was tempted to call the Jackson Bluff population C. depressa and the Tamiami population C. tabulata; in effect, disagreeing with Campbell’s synonymy and discounting all of Petuch. The advantage of working with a museum collection is the large number of specimens from multiple locations which allow a researcher to compare variation from one population to another. Although I do not have the proper credentials or live in the vicinity of a major research museum to perform a similar comparison, I do have a relatively large collection from multiple locations to work with. Specimens of C. depressa that I have collected from the Yorktown appear have the same general shape to those specimens that I have from the Jackson Bluff and Tamiami but an intermediate sculpture between the two. Confused? I get that way myself. In the meantime I have classified all three populations as variants of C. depressa until future work can prove otherwise (Figure 4).

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Figure 4. Regional variation in fossil populations of Cancellaria depressa (Tuomey & Holmes, 1856). From left to right: Loc. 471, Jackson Bluff Formation, Liberty County, Florida; Loc. 917, Moore House Member of the Yorktown Formation, Isle of Wight County, Virginia; Loc. 92, Pinecrest Sand of the Tamiami Formation, Sarasota County, Flroida.

As with previous posts, I have listed mollusks that I have collected from both sites reported in the PDFs below.

Jackson Bluff 471.pdf

Jackson Bluff 1018.pdf

REFERENCES

Campbell, Kenneth M. 1985. Alum Bluff Liberty County, Florida. Florida Geological Survey Open File Report 9.

Campbell, Lyle. 1975. Check List of Marine Pliocene Mollusks of Eastern North America in Plio-Pleistocene Faunas of the Central Carolina Coastal Plain. Geologic Notes (South Carolina Division of Geology) Vol. 19, No. 3.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Dall W.H. 1890-1903. Contributions to the Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchie River, Part I: Pulmonate, Opisthobranchiate and Orthodont Gastropods, Transactions of the Wagner Free Institute of Science of Philadelphia 3(1-VI).

Gardner, J. A. 1944. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 1. Pelecypoda, United States Geological Survey Professional Paper 199-A: iv, pages 1-178, plates 1-23

Gardner, J. A. 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 2. Scaphopoda and Gastropoda, United States Geological Survey Professional Paper 199-B: iv, pages 179-310, plates 24-38, [iii]

Gardner, J. A. and T.H. Aldrich. 1919. Mollusca from the Upper Miocene of South Carolina: with Descriptions of New Species. Proceedings of the Academy of Natural Sciences of Philadelphia 71: pages 17-53.

Jones, Douglas S and Allmon, Warren D. 1999. Pliocene marine temperatures on the West Coast of Florida: Estimates from mollusk shell stable isotopes In J.H. Wrenn, J.-P. Suc, and S.A.G. Leroy, eds., The Pliocene: Time of Change. American Association of Stratigraphic Palynologists Foundation, Dallas, Texas, pp. 241-250.

Mansfield, W.C. 1930. Miocene Gastropods and Scaphopods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 3, 189 pages.

Mansfield, W.C. 1932. Miocene Pelecypods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 8, 233 pages.

Means, Harley. 2002. Introduction to the Geology of the Upper Apalachicola River Basin in Geologic Exposures Along the Upper Apalachicola River. Southeastern Geological Society Field Trip Guidebook 42.

Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Tuomey, M., and F.S. Holmes. 1855-1856 ( 1974 Reprint). Pleiocene Fossils of South-Carolina: Containing Descriptions and Figures of the Polyparia, Echinodermata and Mollusca, Original pages 1-30 and plates 1-12 published in 1855, Original pages 31-152 and plates 13-30 published in 1856, The Paleontological Research Institution Special Publication 12: xvi, 152 pages, 30 plates, [addendum]

Ward, Lauck W. 1993. Pliocene Stratigraphy and Biostratigraphy, Virginia to Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

Yon, J. William. 1965. Adventures in geology at Jackson Bluff. Florida Geological Survey: Special publication 14.

MikeR

Stichting Schepsel Schelp

This year I have been on fewer fossil trips than at any time in my 30 years of collecting. This is mostly because my work is now taking me around the world as far east as Kuwait and as far west as China. This June I was working once more in Brussels, Belgium. With a free day on my hands and having seen much of Brussels on previous trips, I decided to visit a fossil friend and one time trading partner, two hours away in the Netherlands (Holland) in the city of Utrecht. I first started correspondence and trading with Piet Hessel in the late 90s after discovering his website Stichting Schepsel Schelp (http://www.fossilshells.nl) which roughly translates into the International Fossil Shell Foundation. According to his website, Piet first started collecting recent shells along the eastern Atlantic but after he started collecting fossil shells in 1968, the bug obviously bit because of the incredible amount of specimens that he has collected around the world. He turned his townhouse into a museum bought and expanded into the townhouse next door and had basements dug for both because of his ever increasing collection. The museum is now recognized by the Dutch Department of Treasury as non-profit organization.

I always enjoy the Netherlands. I have been fortunate that each time I am there the weather is nice-ish and the vegetation green, lush and blooming. With a GPS I was able to navigatie the narrow streets and the homicidal cyclists of Utrecht as described by the virtual tourist website to the residence of Piet and Jeannette Hessel. Signs in the first floor windows indicated that I had arrived. After a cup a coffee and some small talk, Piet and Jeannette proceeded to show me the largest private collection that I have ever seen. In fact, the collection has grown so large that part of it has been donated to several of the larger regional natural history museums including the Netherlands Centre for Biodiversity Naturalis in Leiden and the Museum of Natural History in Rotterdam. Through the years the Hessels have traveled all over Europe, the US, Venezuela, Central America, the Dominican Republic, Australia, New Zealand and other distant locations collecting fossil shell beds. Their expeditions were not one or two days of collecting during vacation but endeavors lasting three weeks or more. I spent much of my time taking photos of individual specimens and did not capture many pictures of the rows and rows of drawers and shelves. The first floor of the combined townhouses contain nothing but fossil mollusks. The two basements are too low to stand because the engineers involved with the project would not dig them any deeper due stablitiy issues. The strategy is to crouch or sit while viewing items. One basement contains non-mollusk fossils such as echinoids and vertebrates and the other of recent shells.

Below are pictures that I took.

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Piet and Jeannette Hessel at their home and fossil shell museum and downstairs in the sitting room only modern shell room.

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A few of the many fossil showcases.

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Some of the rarer shells from the Eocene of France including Gisortia gigantea far left. Here is a link to this bizarre shell prior to reconstruction (http://www.fossilshe...cuisgast47.html).

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Rarer shells from the Miocene of France.

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Fossil echinoids

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Just a few of the vertebrate fossils for you bone guys. I took these pictures because they were unusual. The first is a Carcharocles megalodon tooth from the Chipola River but not from the Miocene Chipola Formation. The presence of Turritella alumensis in the matrix show that it is from the Upper Pliocene Alum Bluff Formation which is also exposed on the Chipola. This formation (my next post) is Piacenzian Stage and by this time megalodon was extinct so it could be a redeposited tooth in the Jackson Bluff. The next tooth is a rare meg from the French Miocene. To the far right is an impressive Stegodon elephant tusk from the Pliocene of Java.

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Fossil shells from the Miocene of Australia. The first two are pictures of Gigantocypraea gigas the largest cowrie to ever exist. Note the Euro for comparison.

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Fossil shells from the Pliocene Roe Calcarinite of Western Australia. I have a few species from this formation that I received in trade and I have been interested in its fauna since. The deposit is Upper Pliocene Piacenzian stage and is of the same age as the Tamiami, Duplin and Yorktown formations that I have written about in the past. All of these shell beds along with those from the namesake deposits in Italy represented a warm period with rising sea levels which produced a burst of molluscan speciation.

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I have always been interested in taxa which were once plentiful in earlier eras but are represented in the Cenozoic by few representatives such as brachiopods, crinoids and cephalopods. There are some Paleocene, Eocene and Miocene cephalopods in the US however they are mostly found as internal casts. Piet has several cephalopods with original shell preservered. Left to right: Eutrephoceras parisiense and Nautilus sp. from the Eocene of the Paris basin, Nautilus allionii from the French Miocene and Aturia aturi from the Miocene of Italy.

MikeR

Cougars And Big Cypress

During your next Florida vacation, pick up a handful of sand. Each beach will have a different story to tell. The sugary white sand of the Florida panhandle, which I consider the best beach sand in the world originated from the once high and mighty Appalachians, while that from the sheller’s paradise of Sanibel Island and Southwest Florida is from millennia of shells ground down to a fine grit. The beach at Bahia Honda in the Florida Keys is a limey calcium carbonate mud which might one day become limestone. Three million years ago, conditions were no different in the Upper Pliocene. Then the southern Florida shoreline resided in south-central Florida along a line from Sarasota to Fort Basinger. The ancestral Myakka and Kissimmee Rivers deposited sand into a protected basin now occupied by Lake Okeechobee, the Big Cypress Preserve and the Everglades. To the south, which is now the southernmost boundary of the Everglades, existed a coral reef which faced Florida Bay. This formed a carbonate bank similar to that of the modern day Bahamas. Sediment eroded off the reef into the protected embayment and mixed with the siliclastic material coming from the north to form a sandy limestone. This limestone and its fossils were first described by W.C. Mansfield during the construction of the Tamiami Trail in the 1930s and he named it the Tamiami Limestone. Recent work has classified this limestone as the same age as the Lower Pinecrest Beds further north and it is now informally named as the Ochopee Member of the Tamiami Formation. Limestone is indicative of warm tropical water and it is interesting to note that these deposits indicate conditions similar to those of the Caribbean while contemporary sediments less than 100 miles further north were slightly cooler than today’s Gulf of Mexico.

Mollusks compose their shells with either aragonite (CaCO3) or pure calcite. Collectors of fossil shells know that limestone is typically poor for aragonitic shells as it is porous and aragonite is readily dissolved by ground water. Although this is the case with the Ochopee, aragonitic shells leave internal limestone casts or “steinkerns” which in many cases can be identified to genus and species and contain many species found in the Pinecrest Beds. On the other hand, marine organisms composed of calcite can be exquisitely preserved in limestone. Calcitic organisms in the Ochopee, which are the desired objects of most collectors of this unit, include oysters, pectens (fig. 1), and echinoids (fig. 2).

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Figure 1. Calcitic bivalves from the Ochopee Member of the Tamiami Formation. From left to right, Hyotissa haitiensis (Sowerby, 1850); Amusium mortoni (Ravenel, 1844); Nodipecten collierensis (Mansfield, 1931). All from Collier County, Florida

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Figure 2. Echinoids from the Ochopee Member of the Tamiami Formation. From left to right, Encope tamiamiensis Mansfield, 1932; Rhncholampas evergladensis (Mansfield, 1932); Arbacia improcera (Conrad, 1843). All from Collier County, Florida.

Several quarries in the Big Cypress Swamp area between Lake Okeechobee and the Everglades once mined the limestone for road material. I first visited one such quarry in 2000 (locality 496). This state burrow pit, quarried for limestone road fill, still contains some of the crushed material mined in the 90s however, the 12-15 foot tall piles of limestone are but a quarter of the size when I last visited late in 2011 (fig. 3). At one time, piles of partially crushed limestone full of fossils could be found dotting the surrounding area. Once the few remaining piles are diminished by the county department of transportation, there will be few if any collectible sources for these deposits. Perhaps the pits will go the way of the Florida Panther, whose protected habitat is contained within the Everglades and Big Cypress Preserves. Nothing more than a geographically restricted population of the puma, a large cat which once inhabited almost all of North America, it is now only found in the eastern US by this small and threatened genetically isolated population.

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Figure 3. Images from Locality 496, Collier County, Florida

Through the years, I have collected from several of the aforementioned spoil piles in the region and as I did in my last post about the Lower Pinecrest Beds, I have decided to attach a comprehensive fauna list of species in my collection from all of my Ochopee localities (Loc. 496, 925, 926).

Fauna list Ochopee.doc

REFERENCES

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Dall W.H. 1890-1903. Contributions to the Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchie River, Part I: Pulmonate, Opisthobranchiate and Orthodont Gastropods, Transactions of the Wagner Free Institute of Science of Philadelphia 3(1-VI).

Jones, Douglas S and Allmon, Warren D. 1999. Pliocene marine temperatures on the West Coast of Florida: Estimates from mollusk shell stable isotopes In J.H. Wrenn, J.-P. Suc, and S.A.G. Leroy, eds., The Pliocene: Time of Change. American Association of Stratigraphic Palynologists Foundation, Dallas, Texas, pp. 241-250.

Mansfield, W.C. 1930. Miocene Gastropods and Scaphopods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 3, 189 pages.

Mansfield, W.C. 1931. Some tertiary mollusks from southern Florida. Proceedings of the United States National Museum, v. 79.

Mansfield, W.C. 1931. Pliocene Fossils from Limestone in Southern Florida in Shorter Contributions to General Geology, USGS Professional Paper 170, 11 pages.

Mansfield, W.C. 1932. Miocene Pelecypods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 8, 233 pages.

Mansfield, W.C. 1936. Stratigraphic Significance of Miocene, Pliocene, and Pleistocene Pectinidae in the Southeastern United States, Journal of Paleontology, Vol 10, No. 3, 24 pages.

Mansfield, W.C. 1939. Notes on the Upper Tertiary and Pleistocene Mollusks of Peninsular Florida, Florida Geological Survey Bulletin 18, 128 pages.

Missimer, Thomas M. 1992. Stratigraphic relationships of sediment facies within the Tamiami Formation of Southwest Florida: Proposed intraformational correlations. Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Olsson, A.A. 1967 (1993 Reprint). Some Tertiary Mollusks from South Florida and the Caribbean, Originally - Bulletins of American Paleontology 54(242), The Paleontological Research Institute Special Publication 19: pages 11-75, 9 plates

Olsson, A.A., and A. Harbison. 1953 (1990 Reprint). Pliocene Mollusca of Southern Florida with Special Reference to Those from North Saint Petersburg, with special chapters on Turridae by W.G. Fargo and Vitinellidae and Fresh-water Mollusks by H.A. Pilsbry, The Academy of Natural Sciences of Philadelphia Monographs 8, The Shell Museum and Educational Foundation, 457 pages, 65 plates

Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217): pages 509-574, plates 77-83

Olsson, A.A., and R.E. Petit. 1968 (1993 Reprint). Notes on Siphocypraea, Originally - Special Publication 9, The Paleontological Research Institute Special Publication 19: pages 77-88.

Petuch, E.J. 1982. Notes on the molluscan paleontology of the Pinecrest Beds at Sarasota, Florida with the description of Pyruella, a stratigraphically important new genus: Proceedings of the Academy of Natural Sciences of Philadelphia, v. 134, p. 12–30.

Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.

Petuch, Edward J. 2007. The Geology of the Everglades and Adjacent Areas. CRC Press.

MikeR

Three million years ago the Mid-Piacenzian warming stage was in effect for South Florida. The cool water fauna exemplified by Chesapecten found in Bed 11 of the Tamiami Formation was replaced by a warmer more diverse fauna, which formed extremely fossiliferous shell beds in the Sarasota and Kissimmee River regions of Florida. These deposits are called the Pinecrest beds after the tiny city of Pinecrest, Florida where they were first described by Axel Olsson in 1964. The Pinecrest is known to form 11 distinct beds that have a tendency to be dominated by one or two species (fig. 1) and together have the highest diversity of any shell deposit in the United States with an estimated total of 1000-1200 different molluscan species.

As described by Ed Petuch in 1982, the Pinecrest shell beds at the famous APAC pit were as follows:

Bed 1 Lower Pleistocene Caloosahatchee fauna

Bed 2 Layer of the oyster Hyotissa haitensis

Bed 3 Sandy layer with double valved Mytilus conradiana

Bed 4 The Black layer. A shell bed with a brackish water fauna stained black from sulfide reduction. Richest vertebrate fauna above bed 11.

Bed 5 A layer of the filter feeding gastropods Vermicularia recta

Bed 6/7 The thickest and most diverse shell bed

Bed 8 Vermicularia recta

Bed 9 Layer of Hyotissa haitensis

Bed 10 Rich and diverse shell bed.

Bed 11 Colder water fauna including Ecphora and Chesapecten.

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Figure 1. Diagnostic fossil shells from the Pinecrest Beds of the Tamiami Formation. From left to right: Mytilus conradiana (d'Orbingny, 1852) Bed 3; Vermicularia recta Olsson & Harbinson, 1953 Bed 8; Hyotissa haitensis (Sowerby, 1850) Bed 9. All from Locality 92, APAC Mine, Sarasota County, Florida.

As popular as these deposits are for the fossil shell collector, their geology and paleontology are a mess. Formations are described based on the lithology (type of rocks) and uncomformities (time gaps) not their fossils and yet numerous formations of similar lithology and members of patchy distribution have been named based solely on fossil content. Four distinct biozones, however do occur which document three extinction events, two of which had significant fauna turnover. My personal impression of Florida geology is that it is like trying to fit a square peg in a round hole. So many changes were occurring during the Florida Plio-Pleistocene that it is difficult to apply conventional rules. Add to the mix a plethora of books aimed at the amateur market that excessively split species and make ecological interpretations that are not backed by experimental proof or peer-review. With all of the taxonomic splitting that has occurred, many hundreds of species are listed as extinct giving the impression that today’s Floridian fauna is much diminished from the Pliocene. Comparison of valid Pliocene species with the modern Floridian molluscan fauna however, shows a near equal number of species between the two. Also with the inflated number of species reported from the Pinecrest beds comes the assumption that the supposed increased diversity in the Pliocene must have been due to tropical conditions. Isotopic studies by Warren Allmon of the Paleontological Research Institute discounts warmer Pliocene water temperature and suggests that the Gulf was slightly cooler due to seasonal upwelling of nutrient rich deep water.

Ed Petuch has described endemic faunas from each Pinecrest Bed which is not supported by most modern-day stratigraphers and paleontologists, but I did not know this when I first identified my APAC finds. My original intent with this blog was to post a new field trip each month but when I jumped into the Tamiami Formation I knew that it was going to be awhile before I would be posting again. I didn’t know at the time it would take me almost a year to accurately identify my collection using classical publications by Dall, Mansfield, and Olsson and tying it all together with the recent work of Lyle Campbell and Lauck Ward. In reporting on these shell beds, I have settled on a general stratigraphic classification similar to that used by Warren Allmon. I call Beds 5-10 the Lower Pinecrest which is separated from Beds 2-4, the Upper Pinecrest, by a gap of tens of thousands of years. In this post I will be reporting on the Lower Pinecrest and describe the Upper Beds when I write about the Pliocene extinction.

In my last post, I described a cool water fauna from lowest bed of the Pinecrest, Bed 11 exposed in a Sarasota County quarry (locality 1016). This layer showed that animal life in Florida was similar to that in the Yorktown Formation of the Mid-Atlantic States which was being deposited at the same time. The succeeding layer Bed 10 also exposed in the same quarry shows significant differences. Whales and sharks which were found in abundance in Bed 11, disappeared due to decreased ocean productivity from the continued closure of the Isthmus of Panama. A thick shell bed began accumulating containing species influenced more from the tropics than from the Yorktown fauna. Large shells are common here as well as warm-water genera such as Strombus, Oliva, Conus, and Cypraea (fig. 2).

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Figure 2. Fossil Shells from Pinecrest Bed 10 at locality 1016. Left to right: Prepared shells; Phyllontous globosus (Emmons, 1858); Sinistrofulgur contrarium (Conrad, 1840); Melongena consors (Sowerby, 1850); Hystrivasum locklini (Olsson & Harbinson, 1953).

Another pit within the same quarry complex (locality 1017) exposed Bed 6/7, the thickest and most diverse of the Pinecrest Beds (fig. 3). These beds accumulated by the concentration of shells due to tides and storms in depressions formed by karst within the underlying Miocene sediments. Currents were constantly washing and re-exposing dead shells while concentrating newer material on top of the old. Corals, barnacles, and bryozoa are also found as well as fragments of more delicate organisms such as crabs and echinoids. Coral in Bed 6/7 tend to be concentrated in certain layers where they lived during a time of less silt and sedimentation. The water however was under the influence silicicastic sediment from the ancestral Myakka and Kissimmee Rivers which was not condusive to coral reef formation. One coral however thrived due to an interesting lifestyle. Free floating Septastrea marylandica larva settled on hermit crab inhabited gastropod shells. The constant motion of the shell by the moving crab did not allow sediment to deposit on top of coral growing upon the shell. All three, crab, gastropod and coral must have made an interesting site (fig. 4).

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Figure 3. Pinecrest Bed 6/7, Locality 1017, Sarasota County, Florida. From left to right: Views of Bed 6/7 spoil piles; Fossil shells from Bed 6/7, Turbinella streami Petuch, 1994 in situ and prepared.

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Figure 4. Corals from the Upper Pliocene Lower Pinecrest Beds, Sarasota County, Florida. Large corals from Bed 6/7 clockwise from back Solenastrea hyades (Dana, 1846), Oculina sarasotana Wiesbord, 1974, Siderastrea pliocenica Vaughn, 1919, Favia fragum (Esper, 1868); Sepastrea marylandica (Conrad, 1837) encrusted gastropods; Heilprinia caloosaensis carolinensis (Dall, 1892) encrusted with S. marylandica. All from Locality 92, APAC Mine, Sarasota, Florida.

In past posts I have organized fauna lists based upon location. Since I re-identified all species from each of my Pinecrest sites (localities 92, 901, 911, 912, 913, 916, 1016, 1017), I have decided to put everything together into one big list. I have within my collection 162 bivalves and 290 gastropods from all of the Pinecrest Beds combined.

Gastropods Upper Pliocene Pinecrest Beds.pdf

Bivalves Upper Pliocene Pinecrest Beds.pdf

REFERENCES

Allmon, Warren D. 1992. Whence Southern Florida’s Plio-Pleistocene shell beds? Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Allmon, Warren D; Rosenberg, Gary; Portell, Roger W.; and Schindler , Kevin S. 1993. Diversity of Atlantic Coastal Plain Mollusks since the Pliocene. Science, vol. 260:1626-1629.

Allmon, Warren D; Emslie, Steven D.; Jones, Douglas S.; and Morgan , Gary S. 1996. Late Neogene Oceanographic change along Florida’s West Coast: Evidence and mechanisms. The Journal of Geology, vol. 104:143-162.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Dall W.H. 1890-1903. Contributions to the Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchie River, Part I: Pulmonate, Opisthobranchiate and Orthodont Gastropods, Transactions of the Wagner Free Institute of Science of Philadelphia 3(1-VI).

Gardner, J. A. 1944. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 1. Pelecypoda, United States Geological Survey Professional Paper 199-A: iv, pages 1-178, plates 1-23

Gardner, J. A. 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina: Part 2. Scaphopoda and Gastropoda, United States Geological Survey Professional Paper 199-B: iv, pages 179-310, plates 24-38, [iii]

Gardner, J. A. and T.H. Aldrich. 1919. Mollusca from the Upper Miocene of South Carolina: with Descriptions of New Species. Proceedings of the Academy of Natural Sciences of Philadelphia 71: pages 17-53.

Jones, Douglas S and Allmon, Warren D. 1999. Pliocene marine temperatures on the West Coast of Florida: Estimates from mollusk shell stable isotopes In J.H. Wrenn, J.-P. Suc, and S.A.G. Leroy, eds., The Pliocene: Time of Change. American Association of Stratigraphic Palynologists Foundation, Dallas, Texas, pp. 241-250.

Mansfield, W.C. 1930. Miocene Gastropods and Scaphopods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 3, 189 pages.

Mansfield, W.C. 1931. Some tertiary mollusks from southern Florida. Proceedings of the United States National Museum, v. 79.

Mansfield, W.C. 1932. Miocene Pelecypods of the Choctawhatchee Formation of Florida, Florida Geological Survey Bulletin 8, 233 pages.

Missimer, Thomas M. 1992. Stratigraphic relationships of sediment facies within the Tamiami Formation of Southwest Florida: Proposed intraformational correlations. Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Olsson, A.A. 1967 (1993 Reprint). Some Tertiary Mollusks from South Florida and the Caribbean, Originally - Bulletins of American Paleontology 54(242), The Paleontological Research Institute Special Publication 19: pages 11-75, 9 plates

Olsson, A.A., and A. Harbison. 1953 (1990 Reprint). Pliocene Mollusca of Southern Florida with Special Reference to Those from North Saint Petersburg, with special chapters on Turridae by W.G. Fargo and Vitinellidae and Fresh-water Mollusks by H.A. Pilsbry, The Academy of Natural Sciences of Philadelphia Monographs 8, The Shell Museum and Educational Foundation, 457 pages, 65 plates

Olsson, A.A., and R.E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas, Bulletins of American Paleontology 47(217): pages 509-574, plates 77-83

Olsson, A.A., and R.E. Petit. 1968 (1993 Reprint). Notes on Siphocypraea, Originally - Special Publication 9, The Paleontological Research Institute Special Publication 19: pages 77-88.

Petuch, E.J. 1982. Notes on the molluscan paleontology of the Pinecrest Beds at Sarasota, Florida with the description of Pyruella, a stratigraphically important new genus: Proceedings of the Academy of Natural Sciences of Philadelphia, v. 134, p. 12–30.

Petuch, Edward J. 1994. Atlas of Florida Fossil Shells (Pliocene and Pleistocene Marine Gastropods). Chicago Spectrum Press.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Petuch, Edward J. 2007. The Geology of the Everglades and Adjacent Areas. CRC Press.

Tucker, H.I. and Druid Wilson. 1932. Some new or otherwise interesting fossils from the Florida Tertiary. Bulletins of American paleontology; v. 18: no. 65.

Tucker, H.I. and Druid Wilson. 1933. A second contribution to the Neogene paleontology of South Florida. Bulletins of American paleontology; v. 18: no. 66.

Tuomey, M., and F.S. Holmes. 1855-1856 ( 1974 Reprint). Pleiocene Fossils of South-Carolina: Containing Descriptions and Figures of the Polyparia, Echinodermata and Mollusca, Original pages 1-30 and plates 1-12 published in 1855, Original pages 31-152 and plates 13-30 published in 1856, The Paleontological Research Institution Special Publication 12: xvi, 152 pages, 30 plates, [addendum]

Ward, Lauck W. 1992. Diagnostic Mollusks from the APAC Pit, Sarasota, Florida in Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Ward, Lauck W. 1993. Pliocene Stratigraphy and Biostratigraphy, Virginia to Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

MikeR

Tamiami Formation, Bed 11

Between 2.5 and 4.5 mya most of Florida south of St. Petersburg was submerged under a cold but warming sea. The series of sand, shell and limestone deposited during this time is named the Tamiami Formation. In April 2011, I visited one of the famed Sarasota shell pits exposing primarily Beds 10 and 11 of the Tamiami Formation, my locality 1016 (fig. 1). My earlier days at APAC were spent collecting from a mixture of beds 1-11, so I was excited that I could collect in a biostratigraphically restricted area to get a better idea if these units contained as diversely an endemic fauna as described in Petuch’s books. Some of the Bed 11 fossils collected are pictured in figure 2 and all mollusks that I found from Bed 11 at Locality 1016 are listed in Table 1.

blogentry-1906-0-25077400-1315075187.jpgblogentry-1906-0-44838600-1315075197.jpgFigure 1. Mixed Bed 10 and 11 Upper Pliocene Tamiami sediments. Locality 1016, Sarasota County, Florida.

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Figure 2. A) Fossils from Tamiami Formation Bed 11; B ) Euvola hemicyclicus (Ravenel, 1834); C) Carolinapecten eboreus (Conrad 1833); C) Ostrea raveneliana Tuomey & Homes, 1855. All from Bed 11, Lower Upper Pliocene Tamiami Formation, Loc. 1016, Sarasota County, Florida.

Table 1. Mollusks (Bivalvia) from Locality 1016, Upper Pliocene Tamiami Formation, Bed 11.

Anomia simplex

Argopecten interlineatus

Argopecten comparilis

Carolinapecten eboreus

Chesapecten madisonius subsp.

Euvola hemicyclicus

Ostrea subdigitalina

Ostrea raveneliana

Plicatula hunterae

Ed Petuch was the first to publish a detailed stratigraphic column of the Tamimi from the old APAC quarry in Sarasota and identified 11 biostratigraphical units. The lowest and therefore oldest unit, Bed 11 is distinctly different from the rest by the lack of aragonitic shells from leaching, a diverse calcitic molluscan fauna including the last appearance of Chesapecten in Florida, massive barnacles, an abundance marine vertebrates and the presence of the mineral phosphorite. Based upon a resemblance to the fauna of Zone 1 Yorktown, Petuch classifies this unit as the Lower Pliocene (Zanclean) Sarasota Member of the Murdock Station Formation. Since this is a biostratigraphic (fauna) designation as opposed to the formal lithographic (rock) description, I follow the classification of this unit as Lower Tamiami Formation (Roger Portell, FMNH, personal communication).

Not all researchers think that Bed 11 is Lower Pliocene. Lauck Ward claims that Zone 1 Yorktown aged sediments are not found south of the Lee Creek Mine and reports of Chesapecten jeffersonius south of LCM are misidentified C. madisonius, septenarius, or hybrids of the two; indicator species of the Upper Pliocene (Lauck Ward, personal communication). He also reported that the associated fauna found in Bed 11 is absent in Zone 1 Yorktown Formation, but present in Zone 2 Upper Pliocene (Piacenzian). Victor Zullo also reported that the barnacle fauna in Bed 11 was related to that of Zone 2 Yorktown Formation.

At first glance, Bed 11 does appear to be of the same age as the Sunken Meadow Member (Zone 1) of the Yorktown Formation. If based solely upon rib number, the plentiful Chesapecten present would be C. jeffersonius. Roger Portell says that all Chesapecten in the collection at FMNH is labeled either C. jeffersonius or C. septenarius; although a systematic study has not been performed (pers. comm.). Lauck Ward states that rib number is not an indicator of species in Chesapecten (L. Ward, personal communication) that other factors such as the strength of the byssal notch and callous buildup on the interior of the shell must also be taken into consideration. One distinct characteristic of the C. madisonius/septenarius complex is the peripheral strength of the ribs (fig. 3). C. jeffersonius lacks strong ribs along the edge of its shell as it ages whereas C. madisonius/septenarius retains distinctive ribing. The closest I find in similarity to the Florida Chesapecten are Chesapecten that I reported from the Rushmere Member of the Yorktown Formation along the Roanoke River in North Carolina. Based upon those similarities, I list the Florida Chesapecten in my collection as hybrid madisonius/septenarius (fig. 4). One additional point; Zone 2 is not rich in vertebrate remains while Tamiami Bed 11 is. This could indicate Lower Pliocene age, however all Carcharodon teeth found on this trip were C. carcharias and not C. megalodon which became extinct at the end of the Lower Pliocene. I would be interested in hearing from anyone who has collected C. megalodon from the lower Tamiami. Maybe Floridian waters were a refuge or breading ground for cetaceans after they diminished for the most part further north during the Upper Pliocene.

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Figure 3. Peripheral Chesapecten rib strength. Left: Chesapecten jeffersonius (Say, 1824), Lower Pliocene Sunken Meadow Member, Yorktown Formation, Loc. 922, Surry County, Virginia; Right: Chesapecten madisonius (Say, 1824) subspecies, Loc. 92, Upper Pliocene, Tamimai Formation, Bed 11, Sarasota County, Florida.

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Figure 4. Chesapecten comparisons. A) Chesapecten jeffersonius (Say, 1824), Lower Pliocene Yorktown Formation, Sunken Meadow Member, Loc. 1015, Hertford County, North Carolina; B ) Chesapecten madisonius (Say, 1824), Upper Pliocene Yorktown Formation, Rushmere Member, Loc. 1015, Hertford County, North Carolina, C) Chesapecten madisonius (Say, 1824) subspecies, Upper Pliocene Yorktown Formation, Rushmere Member, Loc. 1011, Martin County, North Carolina; D) Chesapecten madisonius (Say, 1824) subspecies, Upper Pliocene Tamiami Formation, Bed 11, Loc. 1016, Sarasota County, Florida.

Regardless of the geological context of Bed 11, the presence of Ecphora and Chesapecten indicate that water temperatures were much cooler than the succeeding beds of the Tamiami. Another indicator is the numerous walrus remains that have been found in Bed 11. I found what I first thought was a scrap of manatee rib, an unusual find to say the least in these cold water sediments. As I researched further, I found that sirenian remains have not been reported from the Tamiami. A closer inspection revealed a thin veneer of enamel on my “manatee rib” and the possible presence of globular osteodentine which is indicative of walrus teeth. This leads me to believe that my rib fragment is actually a partial canine tooth of the Pliocene walrus Ontocetus emmonsi Leidy, 1859.

REFERENCES

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Hulbert, Richard C. (ed.). 2001. The Fossils Vertebrates of Florida. University Press of Florida.

Ketcher, Kathleen. 1992. Stratigraphy and Environment of Bed 11 of the "Pinecrest" Beds at Sarasota, Forida in Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Kohno, Naoki and Ray, Clayton E. 2008. Pliocene Walruses from the Yorktown Formation of Virginia and Noarth Carolina, and a Systematic Revision of the North Atlantic Pliocene Walruses in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virgina Museum of Natural History Special Publication No. 14.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Petuch, Edward J. 2007. The Geology of the Evergades and Adjacent Areas. CRC Press.

Ward, Lauck W. 1992. Diagnostic Mollusks from the APAC Pit, Sarasota, Florida in Plio-Pleistocene Stratigraphy and Paleontology of Southern Florida, Florida Geological Survey Special Publication No. 36.

Ward, Lauck W. 1993. Pliocene Stratigraphy and Biostratigraphy, Virginia to Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

Ward, Lauck W. 2008. Synethesis of Paleontological and Stratigraphic Investigations at the Lee Creek Mine, Aurora, NC (1958-2007) in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virgina Museum of Natural History Special Publication No. 14.

Ward, L.W. and Blackwelder, B.W. 1975. Chesapecten, a New “Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. USGS Professional Paper 861.

Zullo, Victor A. and Portell, Roger W. 1993. Paleobiogeography of the Late Cenozoic Barnacle Faunaof Florida in The Neogene of Florida and Adjacent Regions, Florida Geological Survey Special Publication No. 37.

MikeR

Business travel through the years has been very good for me in regards to fossils. My entire collection of Texas Cretaceous and Eocene and west coast Cenozoic was collected when time was available in afternoons or late evenings after work. My latest trip took me to London and Cambridge, England. I cashed in some airline points to take the Mrs. along and the plan was to sightsee in London on the weekend before moving on to Cambridge to work. I consider myself a natural history museum junkie and been to many; the great ones (Smithsonian and American Museum of Nat Hist), small ones which impress nonetheless (Florida Museum of Natural History and University of Nebraska State Museum) and disappointing ones (Utah Museum of Nat Hist and Academy of Natural Sciences). The London Museum of Natural History is on my list however time did not allow a visit even though we drove right by it on our way to our hotel in central London. A definite visit the next time.

I was anticiapating a fossil-less trip, but on my last day while wandering through the lovely and ancient streets of Cambridge, we came across a museum that I did not know existed--The Sedgwick Museum of Natural History. With only an hour left before closing, the wife obliged my obsession and allowed me to wander the halls while she sat in the courtyard to read. The Museum is dedicated to Adam Sedgwick (1785-1873) who became the Woodwardian Chair of Geology at Cambridge University in 1818. The Woodwardian Chair was a position setup at the bequest of Dr. John Woodward (1665-1728) who donated Britain's largest natural history collection at the time to Cambridge and bequeathed money for the establishment of a position to curate the collection. Sedgwick took Woodward's curio cabinets and through his own collecting efforts and acquisitions, turned it into the modern collection it is today. Dual staircases lead to the entrance, one side with carved bears and the other with carved bison from fossiliferous limestone. The museum is of Victorian and Edwardian influence with antique drawers and glass top displays. Each geological age has its own section with primarily British and European fossils. What I really enjoyed was the heavy emphasis on invertebrate fossils of all kinds which is typically ignored in today's dino-centric museums. The museum also contains Charles Darwin's rock collection, Lord Alfred Tennyson's fossil collection, and Ichtyosaurs collected by Mary Anning. Below are pictures from the museum in which I must apologize for the dominance of Cenozoic mollusks, my specialty.

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blogentry-1906-0-18552100-1313955421.jpgDiagram of the Sedgwick Museum

blogentry-1906-0-06495400-1313889944.jpgblogentry-1906-0-03777500-1313889933.jpgFossils from the Red Crag, UK equivalent to the Yorktown, Duplin, and Tamiami Formations.

blogentry-1906-0-12766700-1313890071.jpgblogentry-1906-0-57007800-1313890550.jpgblogentry-1906-0-00759900-1313890561.jpgblogentry-1906-0-53261300-1313890577.jpgMiocene fossils from Belgium, France, and Eastern Europe

blogentry-1906-0-06019900-1313933418.jpgblogentry-1906-0-87695900-1313933432.jpgblogentry-1906-0-68513200-1313933461.jpgblogentry-1906-0-28740700-1313933483.jpg Barton Beds, Late Middle Eocene, UK

blogentry-1906-0-99359500-1313933348.jpgblogentry-1906-0-33138700-1313933363.jpgblogentry-1906-0-04175700-1313933391.jpgblogentry-1906-0-94386800-1313933405.jpgblogentry-1906-0-13212400-1313933556.jpgBracklesham Beds, Early Middle Eocene, UK

blogentry-1906-0-66473600-1313953742.jpgblogentry-1906-0-59103800-1313953769.jpgblogentry-1906-0-23120800-1313953753.jpgLondon Clay, Lower Eocene, UK

blogentry-1906-0-94469400-1313933496.jpgblogentry-1906-0-25609400-1313933510.jpgPtychodus teeth and echinoids, Cretaceous chalk, UK

blogentry-1906-0-56245400-1313933523.jpgAdam Sedgwick

blogentry-1906-0-78044100-1313933543.jpg Fossil collection of Lord Alfred Tennyson

blogentry-1906-0-77221300-1313957630.jpgMy idol, Mr. D on the Ten Pound Note

blogentry-1906-0-01139500-1313957913.jpgSir Isaac Newton's apple tree (by propagation), Cambridge Botanical Gardens.

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Yours truly at the Eagle, a Cambridge public house established in 1525 where airmen of the RAF and US 8th Air Corp signed the walls during WWII and where Jim Watson and Francis Crick would meet over a pint to discuss the structure of DNA in the 1950s.

MikeR

When I first began this blog, my intent was to post field reports and species lists from my collecting trips. Since I was working on my North Carolina material at the time, I started there and was preparing to report on my Alabama trips into the Paleocene and Eocene. Two separate events however changed my directed course. Foremost of the two was my trip to two shell pits in Florida exposing the fabulously rich shell beds of the Tamiami Formation. I have enjoyed researching and reporting about the ecological conditions in the Mid-Atlantic States during the Pliocene and since the Tamiami is of equivalent age to the Yorktown and Duplin Formations which I have recently posted, it is only logical to continue writing about conditions that were occurring further south.

To continue with the Florida Pliocene, however, poses some inherent problems, primarily species identification. Although Florida is blessed with an inordinate supply of fossil shell material, a serious update of the state’s biostratigraphy and paleontology is needed. The work of Ed Petuch can readibly be acquired by amateur enthusiasts however, his work is not peer reviewed and widely criticized by the scientific community (see attached reviews from the Paleontological Research Institute's public download page). This brings me to the second event which made me decide to report on my Florida material, the release of the Florida Paleontological Society’s publication of Mollusca of the Bermont Formation (Middle Pleistocene) by Roger Portell and Alex Kittle of the Florida Museum of Natural History (FMNH).

Review of Cenozoic Seas_Palaios_20(2)_(208-209).pdf

Review Petuch Chesapeake Miocene.pdf

The Bermont Formation is truly unique as it was deposited in the Middle Pleistocene; a time in which deposition was not occurring elsewhere on the eastern US coast. The molluscan fauna which inhabited the warm shallow waters which today is south Florida had an interesting mix of modern shells and endemic species not present before or after this interval. Petuch has researched and published extensively on the Bermont, describing many valid new species, but still woefully over splitting many. With the FPS publication, I had held great hopes that much of this would be clarified and corrected. Alas, when I looked at the species list, a great number of Petuch species were listed including a large number of recognized species in the families of Strombidae (11 species, 6 by Petuch), Melongenidae (12 species, 8 by Petuch) and Olividae (11 Oliva species, 7 by Petuch). It is not that I discount everything by Petuch, but Melongenidae is highly variable. There is a single species of Melongena and one of Sinistrofulgur living in southeastern US today. If one were to compare individuals from the east coast to those on the gulf, he might think that there are several species of each. Variable gradation between individuals that can be seen in a large collection like that at FMNH however, discounts high speciation of these genera. The recognition of so many of Petuch's species has lead me to re-think my use of his publications. To a certain extent I will have to go with a gut feeling on what I might think to be valid and what is not.

In the 80's and early 90's, I made several collecting trips to the APAC shell pit in Sarasota. For the fossil shell collector this was nirvana; a pit that was 1 km wide and 20 meters deep and pumped dry for the quarrying of fossil shells for construction and road fill. Giant piles of fossil shells were everywhere with molluscan diversity of maybe a thousand different species (fig. 1). At the time I used a variety of old references and later Petuch’s Atlas of Florida Fossil shells. Jumping into the Florida Pliocene is going to require me to reassess my species from APAC; a monumental task to say the least. My primary reference in Pliocene shell identification will still remain Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia by Lyle Campbell. In it he describes the Yorktown fauna but lists valid species in Florida as well. This work was printed in 1993 but probably written in the late 80s so many of the Tamiami shells were just coming to light and much of Bermont not yet reported. I will use Petuch’s books when needed (and they will be) and the FMNH Bermont publication for updated generic names. I hope one day Roger Portell will begin compiling an updated work on the Tamiami, however should this occur, I might have to begin a Part 3 for Plio-Pleistocene molluscan identification.

blogentry-1906-0-38368600-1310409843.jpg Figure 1. APAC pit shell beds circa 1986.

MikeR

Approximately 4.5 million years ago, the Albemarle basin in North Carolina was a cool temperate ocean much like that off the coast of Alaska today. Although cold, the offshore waters supported a rich and diverse ecosystem due to the upwelling of deep nutrient rich water. Placopecten clintonius scallops along with young Chesapecten jeffersonius clapped their shells together in an attempt to escape from shell crushing rays. Chesapecten as they aged would eventually develop thick heavy shells and settle onto the ocean bottom to live the life of a sessile filter feeder forming dense beds along with the giant oyster Ostrea compressiostrea which lived a similar life. The predatory snail Ecphora quadricostata moved through the soft mud in search of bivalve prey. It would use its foot to envelope clams or slow snails and then using a rasping radula, drill a hole into mollusk shells giving it access to its victim’s vulnerable internal organs. Large whales swam these waters and were preyed upon by giant megalodon sharks and seals played in the water while searching for food. Bones and teeth of predator and prey scattered the sea bottom.

Global climate conditions however would change this idyllic setting. Temperatures began to drop as did sea level when polar ice caps and glaciers began to increase. What were near-shore seas became land and stayed that way for 500,000 years. When temperatures began to increase and the Albemarle basin became ocean once more, the whales were gone and megalodon extinct. Ecphora quadricostata survived but not Placopecten. Chesapecten and Ostrea returned but changed by evolution due to the environment that they retreated to during this ice age. The water was still cold but warmer. A richer molluscan fauna now existed but with much fewer sharks and fish as the waters were possibly less productive. A physical barrier separated subtropical waters in South Carolina from temperate conditions in Virginia however warm cycles would occur allowing for exotic southern species to thrive in the north at least for awhile. Barrier islands formed changing the conditions in this area of North Carolina from open marine to brackish. The molluscan fauna was replaced by species adapted to lower salinity, but returned when global temperatures raised sea levels once more. The late Pliocene however, was a tumultuous time. The final closure of the Isthmus of Panama was occurring changing oceanic currents forever. Whether this changing ocean pattern increased global ice or some other factor was the cause, the resulting sea drop was rapid and extreme with as much as 80% of the molluscan fauna becoming extinct. When the seas returned once more towards the end of the Pliocene, only a handful of species were present and great lineages such as Chesapecten and Ecphora were forever gone.

One of the reasons I enjoy fossil collecting is the story that rocks and fossils tell. The scene that I just described is depicted within the Yorktown Formation found within northeast North Carolina and Virginia. The first paragraph describes the topic of my last post, Zone 1 Yorktown Formation, the second paragraph and which I will be reporting in this entry, Zone 2. W.C. Mansfield divided the Yorktown into two biozones (Zones 1 & 2) while Ward and Blackwelder further divided Zone 2 into three members the Rushmere, the Mogarts Beach, and the Moore House. The Rushmere member outcrops along the Roanoke and Meherrin Rivers which I have been writing about in my last few posts. The Mogarts Beach member is present in one spot on the Meherrin, but since it is the brackish silty clay that succeeds the Rushmere, only the bivalve Mulinia congesta (Conrad, 1833) occurs in any great numbers and won’t be discussed here. The Moore House member represents the return of marine conditions and the Zone 2 fauna to the area that I also mentioned above. It includes the fantastic shell beds formerly exposed in the Chuckatuck quarry in Virginia but since it does not outcrop along the Meherrin or Roanoke Rivers, I will report about it at a later date.

I have collected the Rushmere member of the Yorktown Formation across North Carolina and Virginia. Zone 2 guide fossils include Chesapecten madisonius (Say, 1824), Chesapecten septenarius (Say, 1822) Ostrea raveneliana Tuomey & Holmes, 1855, and Ecphora quadricostata (Say, 1824) (fig. 1). Along the Meherrin River the contact between Zones 1 and 2 can be readily observed. The Rushmere exposures here are typical of this member; silty sands thick with shells of large bivalves and a few gastropod species scattered here and there (fig. 2). Of note is the presence of Glossus fraternus (Say, 1824), a taxa which is today represented by only a single species found in the North Atlantic and indicating that perhaps the Rushmere here at the Meherrin was colder than coastal waters today.

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Figure 1. Guide fossils of the Rushmere Member of the Yorktown Formation. A) Chesapecten madisonius (Say, 1824), loc. 1015, Hertford County, North Carolina; B ) Chesapecten septenarius (Say, 1822), loc. 1011, Martin County, North Carolina; C) Ecphora quadricostata (Say, 1824) [image courtesy of nala] ;) , loc. 1011, Martin County, North Carolina.

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Figure 2. Fossil gastropods from Locality 1015, Rushmere Member of the Yorktown Formation, Hertford County, North Carolina. A) Boreotrophon tectricus (Conrad, 1832); B ) Scalaspira strumosa (Conrad, 1830); C) Ptychosalpinx altile (Conrad, 1832); D) Urosalpinx trossula (Conrad, 1832); E) Lyrosoma sulcosa (Conrad, 1830).

The Rushmere is also present on the Roanoke River however the fauna is somewhat different than most that I have collected and therefore quite interesting. At locality 1010, the Rushmere sits directly upon Upper Cretaceous sediments probably Black Creek Formation. Although macrofossils are not present in the Cretaceous here, vertebrates are plentiful along the lower Rushmere contact. Since the Zone 2 Yorktown is vertebrate scarce, bones and teeth were probably derived from Zone 1 Yorktown or the Eastover Formation and deposited as lag during the beginning of the Rushmere transgression. Some in my party found small meg teeth at this site. I found a mid-sized but very worn meg, bone pieces, and a nice dolphin tooth (fig. 3) that I identified based upon an almost identical tooth figured in the VMNH Lee Creek publication (Whitmore & Kaltenbach, p.22, fig. 66a).

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Figure 3. Cf. Turiops sp. Tooth. Mio-Pliocene lag at base of the Rushmere Member of the Yorktown Formation. Loc. 1010. Halifax County, North Carolina.

I found several unusual shells at Roanoke River locality 1011 (fig. 4). Larger gastropods were common particularly carnivorous volutes and moon shells. Although I have collected these in the uppermost Zone 2 at Chuckatuck and they have been reported in the Rushmere, I have never personally collected volutes in the Rushmere. Preservation was not the best, but they were unusual enough to collect (fig. 5). An unusual Chesapecten is also found here. The population of Chesapecten madisonius at this locality has a maximum of 12 ribs compared to the usual 16 (fig. 6). The difference can be seen by comparing figure 6 to figure 1A. Lauck Ward who originally named Chesapecten has found these only in this area and thinks they are a hybrid ("race") of C. madisonius and C. septenarius, probably deserving a subspecific status (L. Ward, personal communication). I find that they are very similar to Florida Chesapecten and I will describe these in more detail in the future, but the presence of a more diverse gastropod population along with Chesapecten resembling southern forms could indicate a period of intermittent warmth. This is only conjecture on my part but if so, these conditions were not to last as the regression and then transgression 800,000 years later that is captured in the Chowan River Formation was to decimate this fauna.

blogentry-1906-0-36914600-1308164062.jpgFigure 4. Shell bed at Locality 1011, Rushmere Member of the Yorktown Formation, Martin County, North Carolina.

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Figure 5. Fossil gastropods from Locality 1011, Rushmere Member of the Yorktown Formation, Martin County, North Carolina. A) Volutifusus obtusa (Emmons, 1858), B ) Volutifusus mutabilis (Conrad, 1834), C) Euspira perspectiva (Rogers & Rogers, 1837).

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Figure 6. Chesapecten madisonius subsp.? Ward pers. comm. Loc. 1011, Rushmere Member of the Yorktown Formation, Martin County, North Carolina.

Molluscan fauna lists from the region below:

Mollusca Locality 1011.pdf

Mollusca Locality 770.pdf

Mollusca Locality 1013.pdf

Mollusca Locality 1015.pdf

REFERENCES

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Christie, Max. 2009. Ecological Interactions Across a Plio-Pleistocene Interval of Faunal Turnover: Naticid Cannibalism North and South of Cape Hatteras, North Carolina. Departmental Honors in Interdisciplinary Studies Thesis, The College of William and Mary.

Mansfield, W.C., 1943 [1944]. Stratigraphy of the Miocene of Virginia and the Miocene and Pliocene of North Carolina in Gardner, Julia ed. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina. USGS Professional Paper 199A, p. 1-19.

Molnar, Peter. 2008. Closing of the Central American Seaway and the Ice Age:

A critical review. Paleoceanography Volume 21.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Schmidt, D. N., 2007. The closure history of the Panama Isthmus: Evidence from isotopes and fossils to models and molecules. In: Williams, M., Haywood, A. M., Gregory, J. F., and Schmidt, D. N. Eds.), Deep time perspectives on climate change - marrying the signal from computer models and biological proxies. Geological Society of London, London.

Ward, Lauck W. 1992. Tertiary Molluscan Assemblages from the Salisbury Embayment of Virginia. Virginina Journal of Science, Volume 43, no. 1B.

Ward, L.W. and Blackwelder, B.W. 1975. Chesapecten, a New “Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. USGS Professional Paper 861.

Ward, L.W. and Blackwelder, B.W. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group-Middle Atlantic Coastal Plain. USGS Bulletin 1482-D.

Whitmore, Frank C. Jr and Kaltenbach, James A. 2008. Neogene Cetacea of the Lee Creek Phosphate Mine, North Carolina in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virgina Museum of Natural History Special Publication No. 14.

MikeR

If anyone comes away with a message from reading my blog, it should be that things change. The earth is constantly going through periods of warming and cooling which affect not only sea levels and ocean currents, but also organisms adapted to their environment. Profound environmental change leads to extinction, but pushes evolutionary factors to refill empty niches with new species. Rivers in the Albemarle basin of northeastern North Carolina cut through four distinct shell beds that trace molluscan evolution in response to environmental change. I have discussed two of these already; the Upper Miocene Eastover Formation and the Upper Pliocene Chowan River Formation. The other two are within the Yorktown Formation bookended by the Eastover and Chowan River Formations.

One of the giants in American paleontology, Wendell Mansfield, proposed a zonation of the Yorktown based upon different faunas within two biozones. The lower of these was later named the Sunken Meadow Member of the Yorktown Formation by Ward and Blackwelder and is presently classified as Zanclean (Lower Pliocene) in age. The environment was cool temperate, similar to that in the Aleutian Islands. Although water temperatures were colder than presently exist in the Mid-Atlantic region, productivity was high as its shell beds are rich in individuals, albeit lower in diversity than the overlying Zone 2. The Sunken Meadow Member was rich with marine vertebrates as well and is the member of the Yorktown from which shark, bird, whale, dolphin and seal remains are found at the Lee Creek Mine.

I have collected the Sunken Meadow Member along the James River in Virginia and in the Lee Creek Mine and had the opportunity to collect similar deposits during my 2010 North Carolina river trip. Vertebrates were not very common that day along the Meherrin as I suspect enterprising locals keep the area swept clean, however for a fossil shell collector, the typical Zone 1 guide fossils were ever present (fig. 1). I did not spend a lot of time that day collecting Zone 1 as I was more interested in the much more diverse overlying Zone 2 fauna, so the only other shell that I found in the Sunken Meadow Member were fragmental Turritella bipertita Conrad, 1844 from locality 1015.

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Figure 1. Guide fossils of the Sunken Meadow Member of the Yorktown Formation. A) Chesapecten jeffersonius (Say, 1824), loc. 1014; B ) Placopecten clintonius (Emmons, 1858), loc. 1014; C) Ostrea compressiostrea Say, 1824, loc. 1014; D) Ecphora quadricostata (Say, 1824), loc. 1015. All from Hertford County, North Carolina.

REFERENCES

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Mansfield, W.C., 1943 [1944]. Stratigraphy of the Miocene of Virginia and the Miocene and Pliocene of North Carolina in Gardner, Julia ed. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina. USGS Professional Paper 199A, p. 1-19.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Ward, Lauck W. 1992. Tertiary Molluscan Assemblages from the Salisbury Embayment of Virginia. Virginina Journal of Science, Volume 43, no. 1B.

Ward, L.W. and Blackwelder, B.W. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group-Middle Atlantic Coastal Plain. USGS Bulletin 1482-D.

MikeR

In 2010, I had the opportunity to collect on the Roanoke and Meherrin Rivers which feed into Albemarle Sound in northern coastal North Carolina. Boating on both of these rivers is always enjoyable due to large numbers of bald eagles on the Roanoke and extensive stands of Cypress trees on the Meherrin (fig. 1). Besides their natural beauty, between the two are exposed a little more than six million years of strata stretching from the Upper Miocene to Upper Pliocene.

blogentry-1906-0-51970400-1304784521.jpgFigure 1. Cypress swamp along Meherrin River.

The oldest of these, is an exposure of the Cobham Bay Member of the Eastover Formation on the Meherrin River. Earlier workers classified these sediments as the St. Marys Formation, which are exposed in the Chesapeake Bay area, however Ward and Blackwelder formerly named them the Eastover Formation due to their younger age and distinct fauna. The 8.7 million year old Cobham Bay Member is found in this part of North Carolina, coastal Virginia and southeast Maryland and was deposited during temperate/subtropical conditions. The Cobham Bay Member is also notable in producing marine vertebrate remains and cemented plates of the guide fossil Chesapecten middlesexensis (Mansfield, 1936) along the James River in Virginia (fig. 2). The Meherrin Eastover site was exposed with the Yorktown Formation at Locality 1013. Most of my collecting efforts at this site were directed to Zone 2 Yorktown, which I will be reporting on shortly, but I did find an excellent example of the guide fossil Placopecten princepoides (Emmons, 1858). Actually I was unaware until researching this post that this is the type locality for P. princepoides, first discovered and described by Ebenezer Emmons prior to the American Civil War. At that time, Emmons was North Carolina’s first state geologist, but had made his name in New York where as Chief State Geologist named the Adirondacks (1838) and Taconic Mountains (1844).

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Figure 2. Chesapecten middlesexensis (Mansfield, 1936), Upper Miocene Cobham Bay Member of the Eastover Formation, Loc. 922, Surry County, Virginia.

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Figure 3. Placopecten princepoides (Emmons, 1858), Upper Miocene Cobham Bay Member of the Eastover Formation, Loc. 1013, Hertford County, North Carolina.

REFERENCES

Cherniak, DJ. 2005. Ebenezer Emmons (1799-1863)-Rensselaer Class of 1826. http://ees2.geo.rpi.edu/History/emmons.html

Ward, Lauck W. 1992. Tertiary Molluscan Assemblages from the Salisbury Embayment of Virginia. Virginina Journal of Science, Volume 43, no. 1B.

Ward, Lauck W. 1992. Molluscan Biostratigraphy of the Miocene, Middle Atlantic Coastal Plain of North America. Virginina Museum of Natural History, Memoir No. 2.

Ward, L.W. and Blackwelder, B.W. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group-Middle Atlantic Coastal Plain. USGS Bulletin 1482-D.

MikeR

Chowan River Formation

At the end of the Pliocene, two sea level pulses occurred. With the first of these, temperatures cooled and sea level dropped as much as 25 ft, and in the process caused the extinction of approximately 80 percent of the cool-temperate Yorktown molluscan fauna including famed genera such as Chesapecten and Ecphora. When the sea rose once more during the latest Pliocene, temperate conditions returned and a mix of survivors, sub-tropical emigrants, and a few new molluscan species repopulated the area. These deposits, named the Chowan River Formation by Ward and Blackwelder, are limited to southern Virginia and northern North Carolina. Campbell (2010) reports 250 molluscan species in the Chowan River Formation compared to the preceding 519 species in Zone 2 Yorktown sediments.

Most exposures of the Chowan River Formation are river sites and have disappeared to development. I had the opportunity to visit a rare exposure on the Roanoke River in 2010. Unfortunately it was late in the day and I was only able to collect for about 15 minutes. My collection from this site (locality 1010) is composed of a few large shells that I collected and associated small species from the screened sediment (Table 1).

Table 1. Fossil species from Locality 1010, Upper Pliocene Chowan River Formation,

Martin County, North Carolina.

Carolinapecten eboreus bertiensis

Mercenaria carolinensis

Pitar sayana

Mulinia lateralis

Nuculana acuta

Nucula proxima

Ostrea raveneliana

Glycymeris subovata hummi

Pseudomiltha anodonta

Varicorbula chowanensis

Ptycosalpinx chesapeakensis

Chesaconcavus cf. proteus

Septastrea marylandica

Of interest was a Ptychosalpinx chesapeakensis Campbell 1993 that I found as float (fig. 1). Neither Campbell nor Ward list the genus Ptychosalpinx after the Yorktown extinction however this is not the first time that I found a member of the same genus in Chowan River deposits. In 1997, I found a small Ptychosalpinx altile (Conrad, 1832) (fig. 2) at Lee Creek Mine (locality 171). Petuch (2004) reported a large Chowan River fauna from the Lee Creek Mine however Ward (2008) discounts almost all of it as Lower Pleistocene James City Formation since the Chowan River Formation at Lee Creek Mine is a thin sandstone and only small mollusks are preserved. Since only calcitic fossil shells (pectens, oysters, Ecphora) are preserved in the Yorktown exposures at Lee Creek and the only aragonitic shells are from the Lower Pleistocene James City Formation, it must have come from the Chowan River Formation.

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Figure 1. Ptychosalpinx chesapeakensis Campbell 1993 Locality 1010, Chowan River Formation, Martin County, North Carolina. a)apertural view b)abapertural view

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Figure 2. Ptychosalpinx altile(Conrad, 1832)Locality 171, Chowan River Formation, Beaufort County, North Carolina. a)apertural view b)abapertural view

After the Chowan ocean high-stand another regressive/transgressive pulse occurred issuing in the previously reported Waccamaw Formation.

REFERENCES

Buzas, Martin A. and Culver, Stephen J. 1994. Species Pool and Dynamics of Marine Paleocommunities. Science.264.5164.1439.

Campbell, Lyle. 1993. Pliocene Molluscs from the Yorktown and Chowan River Formations in Virginia. Virginia Division of Mineral Resources Publication 127.

Campbell, Lyle, Campbell, Matthew, and Campbell, Sarah. 2010. Molluscan Diversity of the Yorktown Formation (Pliocene) in Virginia: an Update. Paper No. 77-10. Northeastern Section (45th Annual) and Southeastern Section (59th Annual) Joint Meeting GSA.

Krantz, D.E., 1991. A chronology of Pliocene sea-level fluctuations: The U.S. Middle Atlantic Coastal Plain record: Quaternary Science Reviews, v. 10.

Petuch, Edward J. 2004. Cenozoic Seas. CRC Press.

Ward, Lauck W. 1993. Pliocene Stratigraphy and Biostratigraphy – Virginia to Florida in the Neogene of Florida and Adjacent Regions. Florida Geological Survey Special Publication No. 37.

Ward, Lauck W. 2008. Synethesis of Paleontological and Stratigraphic Investigations at the Lee Creek Mine, Aurora, NC (1958-2007) in The Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virgina Museum of Natural History Special Publication No. 14.

Ward, L.W. and Blackwelder, B.W. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group-Middle Atlantic Coastal Plain. USGS Bulletin 1482-D.

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