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Whittington, H.B. and Evitt, W.R., 1953. Silicified Middle Ordovician trilobites (Vol. 59). Geological Society of America. https://pubs.geoscienceworld.org/books/book/65/Silicified-Middle-Ordovician-Trilobites (free download until June 30, 2020) Whittington, H.B., 1959, Silicified Middle Ordovician trilobites: Remopleurididae, Trinucleidae, Raphiophoridae, Endymioniidae. Bulletin of the Museum of Comparative Zoology at Harvard College. vol. 121, pp. 369-496. https://www.biodiversitylibrary.org/part/32962#/summary https://www.biodiversitylibrary.org/page/4778534#page/501/mode/1up Hu, C.H., 1974, September. 635. Ontogenies of two Middle Ordovician trilobites from the Edinburg Formation, Virginia. In Transactions and proceedings of the Paleontological Society of Japan. New series (Vol. 1974, No. 95, pp. 353-363). Palaeontological Society of Japan. https://www.jstage.jst.go.jp/article/prpsj1951/1974/95/1974_95_353/_article/-char/ja Hu, C.H., 1976, April. 657. Ontogenies of three species of Silicified Middle Ordovician trilobites from Virginia. In Transactions and proceedings of the Paleontological Society of Japan. New series (Vol. 1976, No. 101, pp. 247-263). Palaeontological Society of Japan. https://www.jstage.jst.go.jp/article/prpsj1951/1976/101/1976_101_247/_pdf/-char/ja https://www.jstage.jst.go.jp/article/prpsj1951/1976/101/1976_101_247/_article/-char/ja/ Bruton, D.L. and Nakrem, H.A., 2005. Enrollment in a Middle Ordovician agnostoid trilobite. Acta Palaeontologica Polonica, 50(3). http://agro.icm.edu.pl/agro/element/bwmeta1.element.agro-article-e5a5ef53-3af9-4efd-b8b3-ca3006e0e32d/c/app50-441.pdf Yours, Paul H.

Found this any info is appreciated. No limestone and not much quartz in the area this was found. Everything about it is very hard and possibly silicified. Thanks Jason

Hi, all, A friend over on the Facebook group "Great Lakes Rocks and Minerals" recently posted this little silicified pebble she found along the shore of Lake Michigan, northern lower peninsula. The tiny pores got several of us on the group curious about whether we could narrow down a possible ID. Someone initially suggested heliolitid, but I think we ruled that out because there doesn't seem to be enough room between corallites for coenenchyme. We decided it must be some species of small-celled favositid, but is it possible to narrow beyond that? (My gut says probably not, since we don't have thin sections or better views!) I was curious about Astrocerium (referred to as Favosites venustus in older descriptions). It's described from the Silurian (Niagaran) of Michigan, which seems to fit with this style of silicification. Also, I think I see what might be interpreted as spinules in some of the corallites, but maybe this is just an effect of silicification. Plus, I guess spinules are pretty common in favositid species, so it could be any number of small-celled species of Favosites or Emmonsia. If anyone has examples of Astrocerium from their collection, I would love to see photos! P.S. Hope it's okay to tag you two, @TqB and @FossilDAWG -- wasn't sure of other coral experts to ask, though I know they are around! Thanks much! Lisa

Here is a compilation of two trips to the Payson, Arizona area last month. Early in May, I led a Saturday and Sunday trip for the Southwest Paleontology Society. Since everyone left by lunchtime on Sunday, I headed over to a local cave, Redman Cave, carved in the Devonian Martin Formation to look for nearby fossils. Although I have been in the cave twice, why go where you cannot collect fossils and you might not have enough oxygen to breath. The cave is connected to the disappearance of one of the FBI’s ten most wanted fugitives, Robert Fisher who murdered his family in Scottsdale and left his dog and car nearby. After searching several caves, no trace of him was found. Photo 1: Redman Cave. Photo 2: J. Redman’s grave next to cave. Photo 3: see Fisher’s most wanted poster. link. Photo 4: after visiting the cave, I looked for outcrops of the early Permian Fort Apache Member of the Schnebly Hill Formation. I found this 4.75 inch long silicified sponge branch that was fully exposed after using four gallons of pool acid. Photo 5: later in the month, I went back to the Payson area to look for more treasures. From the Fort Apache Member, AKA the Fort Apache Limestone. Dissolving the matrix with acid, I found this silicified Euphemitopsis gastropod that is about 1.5 cm at its widest. Winters possibly found a part of this shell that he identified as a Euphemites. Euphemites have spiral lira, ridges, over the older part of the shell and the younger part of the shell is usually smooth near the curved notch in the aperture, the selinizone. Euphemitopsis have bumps in the newer area near the selenizone. See this reference for the best information about the fossils from the Fort Apache Member. We are finding new species, including sponges, to add to the list: Winters, S.S. (1963). Supai Formation (Permian) of Eastern Arizona. Geological Society of America Memoir, 89, 99 p. link. Photo 6: same Euphemitopsis sp. as above. Photo 7: same Euphemitopsis sp. as above. Photo 8: Euphemitopsis sp. and high spired Apachella sp. Photo about 1.5 cm tall. Photo 9: probable sponge, note spicules in lower part of photo. Sponge about 5 mm across. Photo 10: an unidentified sponge that looks like a Maeandrostia kansasensis sp. found in the Pennsylvanian in central and eastern US and Actinocoelia maeandrina found in the Permian Kaibab Limestone a few hundred feet stratigraphically above the Fort Apache Limestone. Actinocoelia maeandrina photos and description: Finks, R. M. 1960. Late Paleozoic Sponge Faunas of the Texas Region: the Siliceous Sponges. American Museum of Natural History, Bulletin 120 (1): 160 pp., 50 pl. link. Photo 11: an unidentified sponge that looks like a Chaunactis sp. found in the Pennsylvanian Naco Formation in the area. View about 3 cm across. See: Dilliard, Kelly & Rigby, J.K.. (2001). The New Demosponges, Chaunactis olsoni and Haplistion nacoense, and Associated Sponges from the Pennsylvanian Naco Formation, Central Arizona. Brigham Young University Geology Studies. 46. 1-11. link. Photo 12: an unidentified sponge that looks like a Chaunactis sp. found in the Pennsylvanian Naco Formation in the area. View about 2 cm across. Photo 13: an unidentified specimen that looks like a sponge root structure. 7 cm across. Photo 14: detail of above possible sponge root structure. 3 cm across. Photo 15: Parallelodon anarklastum. Blue lines are about 7 mm apart. Photo 16: hinge view of Parallelodon anarklastum. Blue lines are about 7 mm apart. Photo 17: probably Oncochilus insolutus. Blue lines are about 7 mm apart. Photo 18: Lophamplexus? sp. Blue lines are about 7 mm apart. Photo 19: Straparollus (Euomphalus) sp. Blue lines are about 7 mm apart. Photo 20: several Bellerophon sp. shells with tear-drop shaped borings from barnacles, Rogerella. A Blue lines are about 7 mm apart. Photo 21: Palaeonucula levatiformis bivalves with pronounced dentition. Blue lines are about 7 mm apart. Photo 22: Straparollus (Euomphalus) kaibabensis. 4.5 cm across. It looks almost like a coiled cephalopod except for its square aperture. Photo 23: Plagioglypta canna scaphopod. 7 cm long. Photo 24: and now a fossil from a different age found on the trip. Silicified stromatoporoid, a sponge, from the Devonian Martin Formation. The conical bumps on each layer are mamalons so named since they look like breasts. Blue lines are about 7 mm apart. Edit My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Reply to this topic IPS Theme by IPSFocus Theme C The Fossil ForumPowered by Invision Co

The hubbub of the holidays is over. The cold, crisp air has descended here in the Mid-Atlantic. The ground is frozen, but I was craving sunshine and the hunt. With blue skies today and the promise of snow tomorrow, I headed to the one place I was reasonably certain wouldn't be completely frozen -- the Delaware Bay. After all, we put salt on the roads here to keep them from freezing. How cold is it this week? Cold enough to freeze salt water! Here and there, exposed spots dotted the beach and the highest part of the bank, above the high tide line, was still exposed. There were a few pebbles here and there, but the odds of finding something in such scant gravel wasn't promising. I spent the next hour with a friend, exploring the ice formations with cameras. Still, my beloved beach did not disappoint. I found a couple of little favosites corals in the freezing tide pools and a 3-inch chunk of local petrified wood lying along the trash line. There is something ironic about finding petrified - silicified - wood frozen to the beach sand!

The holotype of Anisopyge cooperi Brezinski 1992 Brezinski, D.K. (1992) Permian trilobites from west Texas. Journal of Paleontology, 66(6):924-943 Öpik, A.A. (1967) The Mindyallan Fauna of north-western Queensland. Bureau of Mineral Resources, Geology and Geophysics, Bulletin, 74(1):1-404 PDF TEXT 74(2):1-167 PDF PLATES Öpik, A.A. (1970) Nepeid trilobites of the Middle Cambrian of northern Australia. Bureau of Mineral Resources, Geology and Geophysics, Bulletin, 113:1-47 PDF

This post may hold the record for the longest setup time (unless you count the millions of years of "setup" that are the basis for most of the posts on this forum). The ultimate origin was when I first saw posts from Jim (coralhead) and John (Sacha) showing some stunningly gorgeous silicified fossil corals. This was a treasure to hunt for so unlike the black and gray shark teeth (and other fossils) I had been pulling out of the Peace River and I am always up for new experiences so I contacted the two of them through the forum. In addition to the incredibly encyclopedic knowledge brought to this forum by its members, the social aspect of being able to communicate with other members who share your interest should not be overlooked as another great benefit of TFF. After some discussions about where and how this fossilized coral was found I soon learned that Jim was organizing a trip back in August 2014 for some friends from other mineral and rock tumbling forums who were coming in from out of state to collect some coral. We arrived in southern Georgia and my wife and I were able to meet up with Jim and John in person (two of the nicest guys you're ever likely to meet--a trait that I believe is shared by the vast majority of TFF members). Jim had his hands full organizing the larger group that was coming in from various states to the north so John took us under his wing and Tammy and I were introduced to coral collecting. To call it "hunting" is a bit misleading as the bed of the Withlacoochee River is quite literally paved with chunks of fossilized coral--"shopping" would be a more apt term for what we did. The trick of course is to find some nice pieces where the calcium carbonate (aragonite) coral skeleton has been replaced over time with silicon dioxide as water has picked up this mineral from the silica rich sands and percolated through the corals to slowly transform the chalky white corals to a lustrous glassy chert. A quick strike on a corner with a rock hammer would usually open up a "window" so that we could see what the inner state of the corals looked like within their rocky (and sometimes algae covered) crusts. To say that we had a great time would be an understatement. As you can see from the photo above collected quite a bit--sometimes a bit indiscriminately as we were still novices and did not have a fine tuned eye for what would be a nice looking specimen. One of the goals was to find some pieces of coral that would (though transformed into silica-based chert over the eons) still show some signs of the original coral polyp structure. My wife has a favorite fossil coral pendant she bought in Bali several years ago and we thought it would be fun to try to find something like this ourselves. Unfortunately, our desire to aim for pieces retaining the polyp structure often led us to keep pieces that turned out to be "punky"--where the silica had not entirely replaced the calcium carbonate skeleton. These pieces (while displaying the polyps) were not glassy enough to take cutting and polishing or rock tumbling and have now become "yard rocks" in the back yard. If you missed reading about this outing, check out this post from shortly after our trip (with lots of pretty images): http://www.thefossilforum.com/index.php?/topic/48828-first-coral-hunt/ -Ken

Now that there is a microfossils subforum, I thought I might gather various posts regarding some silicified micros I found recently.... Years ago, I collected a few nice gastropods that were silicified: Because they came from limestone, I figured I could extract many more with muriatic acid. Last summer, I collected some chunks of rock that contained the mollusks: This was the result of the acid bath: There weren't as many snails as I'd hoped, but I was intrigued by the fine detritus. Time to pull out the microscope.

several recent posts regarding artifacts & their identificaton prompted me to dig this specimen out of moth balls: it's both artifact & fossil; the tip section of a chipped stone spear or knifepoint, with a little surprise. The planispiral coiled gastropod preserved in the marine chert or flint probably contributed to it's fracture. It would have been a great artifact had it been complete;only now it's been relegated to "conversation piece". Hope you find it interesting.

Here are some Pennsylvanian gastropods I found years ago that are mostly free of matrix, which is unusual around these parts: Winterset Limestone Jackson County, Missouri They include Hypselentoma, Knightites, and one other that is too tiny to id. Because they are so pristine, I suspected that they were silicified. A scratch on a glass bottle confirmed it. The next thing that came to mind is that if I could find the limestone bed from which they came, I could extract some more with acid. I had returned to the exposure in the past, but I didn't find any more gastropods. I'll have to find them in the matrix. I plan to swing by the area tomorrow....