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Showing results for tags 'mazon creek'.
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After being in and out of the freezer since October this concretion opened yesterday. It is different than anything I've seen before and I haven't been able to match it to anything online or in Wittry's books. I am assuming it is fauna but I'm really not sure. Of course it could be a jellyfish but I've never seen one like this before. Could it be a cephalopod?
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A few weeks ago Mrs R was asking me about TFF. General questions about members and their collections. I did not realise she was fishing for some Christmas gift ideas. I showered her a few of our members collections and she really liked Ralph’s thread “Sometimes You Have To Whack It !!” So yesterday I was very surprised to unwrapped a nice little collection of Mazon Creek fossils . I don’t think there is any rare specimens and unfortunately there was no IDs included. Mazon Creek material is quite rare to pick in the U.K. so she did brilliant and I was very spoiled. I will have to check Ralph’s thread for some IDs. Thanks @Nimravis for inspiring MrsR to purchasing me a wonderful gift . And if anyone has not seen Ralph’s thread it is really interesting a worth spending time looking though it. Cheers Bobby
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Odd looking piece found in the Mazon Creek . Looks to be bark ?? Any ideas ?? Thanks, Phil
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Hey, i just opened a mazon creek nodule with my hammer with a few light taps (since a month going in and out the freezer didnt seem to work) and i found these balls inside. Are they the actual fossil or are the specimens inside the ball? Any answer is appreciated!
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Found this piece in a spoil pile, just the way it is, minus the dirt. Seems to be something, but I can't find any reference. Any ideas ?? I was thinking some kind of seed pod, or cone perhaps ?? Thanks for any help !! Phil
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Below is the fertile fern found in pit 2 fall 2019. It was identified by Fiddlehead early this December as being Crenulopteris mazoniana. The significance being the rarity of fertile ferns in the Mazonia fossil flora. Hope to gain more information on this specimen in the new Flora book once publish.
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This middle Pennsylvanian concretion from Mazon Creek (Francis Creek Shale), was discovered in the fall of 2014 in the Mazon Creek Heritage Site. I could use some help identifying. The preservation is not the best. I see no indication of the existence of wings but I sense there were some.
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Looking to trade for some Mazon creek fossils. Nothing too fancy, but I’d be happy to look at anything you have (besides Essexella). I have some soft bodied animals as well as trilobites from Chengjiang and other lower Cambrian formations in China, as well as a bunch of unprepped material (corals, brachiopods, trilobites) from Paulding, OH and Penn Dixie, NY. PM me if you’re interested and I can send some pictures. Thanks.
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Does anyone have a map demarcating the different Peabody Coal pits in Illinois (i.e. the pits where Mazon Creek fossils are found)? I can't seem to find one online.
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Mazon Creek Best Of The Best Illilepas Damrowi Schram, 1975
RCFossils posted a topic in Member Collections
This is an interesting animal that many are not even aware exists in the Mazon Creek deposit. It is a fossil gooseneck barnacle named Illilepas damrowi. Barnacles are known from as early as the Cambrian but are relatively rare in the fossil record. A barnacle is actually a crustacean and are distantly related to lobsters. Modern gooseneck barnacles also have a similar taste to lobster. Like all gooseneck barnacles, Illilepas has a stalk like body and a calcareous head region consisting of plates called a scotum and Tergum. In life, the animals appendages would extend out and filter the water for nutrients. Barnacles will permanently cement themselves to a solid surface. Illilepas is quite rare and only found in the Essex (marine) portion of the Mazon Creek deposit. This first specimen is a fantastic grouping of several individuals still attached to a bivalve (Myalinella meeki).
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I just received this nice Aviculopecten bivalve from Mazon Creek today. What catches my eye is the thing extending from the top of the shell. It almost looks like it could be the siphon protruding outwards. I haven't seen a similar specimen before. Any thoughts?
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Mazon Creek Best Of The Best Esconichthys Apopyris Bardack, 1974
RCFossils posted a topic in Member Collections
The Mazon Creek Deposit is known for many enigmatic creatures. Esconichthys is one of them. The animal has a tadpole shaped body with a usually well preserved pair of eyes. Some specimens preserve 2 pairs of long external gills. Muscle segments called myomeres are sometimes present on laterally preserved specimens. What makes it unusual is that it does not have paired fins. It was originally suggested that Esconichthys may be a larval lungfish or possibly an amphibian. Later studies have stated this is unlikely without offering an alternative placement. Due to the presence of external gills, it is believed that these are likely a larval stage. The largest specimens known can reach almost 8 centimeters. Early collectors referred to these animals as blades or grasshoppers based on their general shape. They are the most common vertebrate found in the Mazon Creek Deposit. Specimens are only known from the marine (Essex) portion. Esconichthys was named to recognize the Earth Science Club Of Illinois (ESCONI).
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This nodule split a while ago. At first I thought it was just a neat looking dud, but after looking closer there appear to be faint radiating lines on the specimen which makes me think it might be plant material, although I have no idea what exactly. Any ideas?
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Mazon Creek Best Of The Best Liomesaspis Laevis Raymond
RCFossils posted a topic in Member Collections
There are currently 3 recognized species of horseshoe crab known from the Mazon Creek deposit. Of these 3, Liomesaspis is the rarest. They are only known from the Braidwood (non marine) portion of the deposit. The most defining feature is the bulbous cardiac lobe. The few specimens that I have seen are often poorly preserved.
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Mazon Creek Best Of The Best Etacystis Communis Nitecki & Schram, 1976
RCFossils posted a topic in Member Collections
Etacystis communis is one of the more unusual animals that can be found in the Essex (marine) portion of the Mazon Creek deposit. Since being described, there has been much debate over what it might be. It has been suggested that it might be a Pterbranch hemichordate, a marine algae or a coelenterate. It is currently assigned as a hydrozoan. Etacystis is commonly referred to by collectors as the “H” animal. Relatively complete specimens bare a resemblance to the letter H. Unfortunately specimens are always incomplete with parts extending off the edges of the concretion. The animal is interpreted as having a main branch called a stolen that may serve as an attachment point to anchor itself into the substrate. It has also been suggested that this animal was free floating as numerous examples have been preserved with the jellyfish Octomedusa The stolen was flexible and would make up one leg of the letter H. The cross bar of the H is referred to as the peduncle. The peduncle bifurcated into 2 arms of different lengths. These arms make up the other leg of the letter H. Also attached to the peduncle is a strange sac like structure with a small aperture. This feature may be a mouth. On a few specimens, wart like bumps are preserved. These bumps could represent stinging cells, suckers or attachment points for tentacles. Etacystis could grow quite large. Based on incomplete specimens, it has been calculated that they could reach lengths of over 15 centimeters.
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Mazon Creek Best Of The Best Kottixerxes Gloriousus Schram, 1971
RCFossils posted a topic in Member Collections
Kottixerxes belongs to a fascinating group of problematic arthropods named Euthycarcinoidea. The current thinking is that they are marine cousins distantly related to insects and myriapods. When Schram first described Kottixerxes in 1971, the Euthycarcinoidea were only know from 2 Triassic aged sites in Germany and Australia. At the time it was described, Kottixerxes was the oldest known Euthycarcinoid. Since that time, Euthycarcinoidea have been found in strata dating back to the Cambrian. In fact there is evidence from a site in Wisconsin that Euthycarcinoids may have been the first creature with the ability to walk on land. Trackways and body fossils have been found that suggest they may have made brief trips out of the water for feeding and possibly egg laying. Based on gut contents, Kottixerxes was a bottom dwelling detritus feeding organism. Kottixerxes is one of the rarest Arthropods found in the marine portion of the Mazon Creek deposit. In 1985, A faunal study was done by Gordon Baird, John Anderson and others to try and determine relative abundance of different Mazon Creek fauna. Using a small army of volunteers, they collected and split nearly 230,000 concretions from the Essex portion of the deposit. Approximately 145,000 of these were “duds”. The other 85,000 were identified and recorded to determine rarity. Out of these 85,000, 2 specimens of Kottixerxes were found making up approximately .002% of the fauna found. The specimen shown may be the finest and largest ever collected. Schram was able to locate nine specimens for his original description. Most are poorly preserved as the carapace must have been quite thin. The largest from his study measured 4 centimeters. They normal average between 2 and 3. This specimen measures slightly over 7 centimeters and is the largest that I am aware of.
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Mazon Creek Best Of The Best Mazonomya Mazonensis Bailey, 2011
RCFossils posted a topic in Member Collections
This next species is the second most common animal found in the Essex portion of the Mazon Creek deposit. While there are over a dozen described bivalves found in the Mazon Creek deposit, Mazonomya is by far the most abundant. It is restricted to the Essex (marine) portion of the deposit, where in some areas have been found to make as much as 70 percent of all bivalves collected. At one collecting site, these clams are so common the area has been nicknamed Chowder Flats. Despite the abundance of specimens, Mazonomya was not formally described until 2011. For years it had been misidentified as a type of bivalve named Edmondia. Current research has shown it is actually a Solemyid. Before formal description, Mazon collectors referred to these bivalves as clam-clams due to the fact that they are often preserved in a death position with both valves opened. Mazonomya is the largest clam found in the deposit . While quite rare, specimens have been found over 4 centimeters in length. preservation can be excellent and in some cases, soft tissue can be preserved. Specimens have been found with preserved “death trails”. Solemyids are still found today in oxygen poor and sulfide rich marshes. This first specimen is the largest in my collection. The valves measure almost 4 centimeters. There is also some evidence of the hinge ligament (soft tissue) between the valves.
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Mazon Creek Best Of The Best Octomedusa Pieckorum Johnson And Richardson, 1968
RCFossils posted a topic in Member Collections
Octomedusa is a type Scyphozoan jellyfish. It is the smallest described species of jellyfish that can be found in the Mazon Creek deposit. The bell can reach a maximum diameter of approximately 2 centimeters. Like all Cnidaria from Mazon Creek, they are only found in the marine portion of the deposit. In the faunal study that I have referenced in previous posts, Octomedusa made up .03% of 230,000 concretions collected. Often times, only the bell is preserved. Well preserved specimens will show 8 tentacles. Depending on orientation in the concretion, some specimens will show a crenulated edge around the bell. Most specimens show very little raised detail and often appear as just a color difference in the rock. A large “X” shaped mouth opening is preserved in some better specimens. This first specimen shows most of the defining features.
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Mazon Creek Best Of The Best Geralinara Carbonaria Scudder, 1884
RCFossils posted a topic in Member Collections
This is a creature that many collectors are not even aware exists in the Mazon Creek Deposit. This unusual animal is commonly known as a whip scorpion. While it is an arachnid and resembles a scorpion , it belongs to a district order called Uropygids. Whip scorpion are incredibly rare in the fossil record. A handful have been described with the earliest known specimens dating back to the Devonian. Any arachnids in the Mazon Creek deposits are considered a rarity. In a faunal study that I referenced in an earlier post, out of 230,000 concretions collected at Pit 11, nine arachnids were found. Uropygids have been estimated to make up approximately 3% of the arachnids found in the Mazon Creek deposit deposit (do the math)! Modern whip scorpions are non venomous and feed on insects, scorpions and in some cases lizards. The long whip like tail helps to detect vibrations. Modern whip scorpion do have an interesting defense weapon. When disturbed, they can spray a solution primarily consisting of acetic acid to thwart off predators. This amazing specimen was found at Pit 11 on May 3rd 1981. The gentleman who collected it, brought it to the Field Museum and had Dr Eugene Richardson study and prep it. Richardson stated that it was the best example that he had ever seen. It was identified by Dr Richardson as Prothelyphonus giganteus. Geralinura and Prothelyphonus are the only 2 Uropygids described from the Mazon Creek Deposit. I am not certain which species it is and really need an arachnid expert to look at it.
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Mazon Creek Best Of The Best Elonichthys Remotus Schultz And Bardack, 1987
RCFossils posted a topic in Member Collections
There are 8 species of paleoniscoids currently described from the Mazon Creek Deposit. While all are relatively rare, the vast majority can be identified as Elonichthys peltigeras and Elonichthys hypsilepus. The other six species are known from very few examples (sometimes only one or two). Almost all Mazon Creek paleoniscoids are juveniles but there are a few larger examples. There are also some isolated body parts of larger individuals. The fact that most Mazon fish are juveniles and often poorly preserved can make identification difficult. To compound the problem there needs to be much more work done as some species may be synonymous with fossils from other areas. The specimen that I am highlighting is an extremely rare species named Elonichthys remotus. At the time it was described (1987) it was known from a single fossil (possibly 2). This is the only other example that I am aware of. It has a rather distinct body when compared to the other Mazon paleoniscoids. The dorsal fin sits far back on the body and begins behind the pelvic fin. The body is also more elongated then other described species. It was collected at Pit 15 which is located a little further South then Pit 11.
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Hello dear members, In this post I want to show you my Mazon Creek Fauna collection. I have only 6 specimens, that I’ve acquired over a long period of time in shows and online. Mazon Creek is definetely my favourite fossil assemblage and I dream, one day, to be able to collect fossils there myself! My specimens are not museum-quality, I’m aware of that, but still can help to give an idea of what a 309 million-year-old soft-bodied biota looked like! Let’s start with the most abundant species of the Essex assemblage: the jellyfish “Essexella asherae”. Known from thousands of concretions, in mine the preservation is fairly good: you can distinguish the bell and the membranous skirt that encloses the tentacles, except their end. Moving on to arthropods, another abundant species is the cycloid “Cyclus americanus”. It is carachterized by a round body, long straight antennae and, at the posterior, two short processes. In my specimen, one antenna and one process can be easily-distinguished. In the echinodermata phylum, there’s only one species described so far: the holoturian (or sea cucumber) “Achistrum sp.”. It has a cylindrical, sack-like body: during preservation it dries, leaving dessication cracks that are replaced whit calcite and are very evident in my specimen. Also clear is the mouth, bearing 15 calcareous plate. The acorn worms (class Enteropneutsa) are hemicordate organisms and their closest relative are echinoderms. These animals have a body that is made up of three main parts: an acorn-shaped proboscis, a short fleshy collar that lies behind it, and a long, worm-like trunk. Mazon Creek’s species “Mazoglossus ramsdelli” is extemely similar to extant species. Finally, I posses two species of bristle worms (Class Polychaeta). The first one is “Astreptoscolex anasillosus”: I’m not 100% sure that the ID is correct, so if you have any suggestion, they are welcome! Anyway, it is a stout worm with the body tapering towards the tail. An eversible proboscis is usually preserved and I think that my specimen features it. The other worm is “Esconites zelus”: it has a long, narrow outline with prominent bristles on its segments. The head has projecting antennae and the jaw apparatus shows wing-like mandibles. In my specimes they are partially preserved, even though not visible in the picture. All right, this is my collection! I know it nothing special, but I hope that it can be appreciated by both Mazon Creek collectors and people who like soft-bodied fossils!
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Mazon Creek Best Of The Best Didontogaster Cordylina Thompson 1979
RCFossils posted a topic in Member Collections
Didontogaster is a polychaete worm (sometimes referred to as bristleworms). The first formal descriptions of Mazon Creek polychaetes did not occur until 1979. At the time they were described, they were the earliest known polychaetes in the fossil record. Since this time, polychaete fossils have been found reaching back as early as possibly the Ediacaran. It is the most common worm found in the Essex portion of the Mazon Creek deposit. It has been classified as belonging to the family Nephtyidae. Members of this family still exist today and are sometimes referred to as cat worms. Didontogaster has a fairly basic body plan. It’s most defining characteristic is a pair of conical shaped jaws that are usually well preserved. Due to the position of the jaws within the body, early collectors nicknamed Didontogaster as a Tummy Tooth Worm. Didontogaster was able to extend it’s jaws outward to feed (see below). It was likely a burrower as they are occasionally found on multiple bedding planes within the concretion. Preserved gut contents show they fed on ostracodes along with plant material. If outstretched, this first specimen would measure around 8 centimeters which is about as big as they get. Most specimens range between 4-5 centimeters.
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I drew this coloring sheet to give out at an upcoming children's program I will be doing at the public library my mom works at. I have done two previous programs over the years on fossils and dinosaurs, but this time I am going to be concentrating on the fossils of Illinois. Of course, this includes our bizarre state fossil, the Tully Monster! The sheet features a Tullimonstrum front and center chasing after an Elonichthys, with a pair of Essexella making their way across the background. It's not the most scientifically accurate drawing, but I hope it will be fun to color! Feel free to download and share- I uploaded both JPEG and PDF versions. (The PDF version also has some descriptive text on it) tully monster coloring page smaller.pdf
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Mazon Creek Best Of The Best Arthropleura Cristata Richardson, 1959
RCFossils posted a topic in Member Collections
Arthropleura is one of the most impressive animals that lived in the Pennsylvanian coal swamps. It is also the largest terrestrial animal known from the Mazon Creek deposit and largest terrestrial arthropod of all time. This giant millipede reach an enormous size estimated to be approximately 2 meters! Unfortunately we do not find complete body fossils. Tergites, limbs and an unusual joint structure that connected the leg to the body (rosette organ) have been found. Any Arthropleura material from Mazon is extremely rare. I would estimate there are only a few dozen specimens known to exist. The earliest reported find of Arthropleura in the Mazon Creek Came from George Langford and Eugene Richardson in 1952. They recovered 2 rosette organs. A few years later a complete leg was found. At first these finds were thought to be unusual shrimp. Richardson was the first to realize that they were indeed Arthropleura. This was the first reported find of Arthropleura in North America. Over the next 2 years a few other specimens were recovered. All were found in the same small area at Pit 1. Richardson formally described Arthropleura cristata in 1959. At the time there was some debate as to if Arthropleura lived its life in water or on land. Many trackways have been found at different sites proving that Arthropleura was terrestrial. Gut contents are known from more complete Arthropleura found at other sites showing that it fed on lycopsid spores. Lycopod cones have a similar appearance to a modern day pine cone. There are a few large coprolites that have been collected from the Mazon Creek deposit that consist of these cone bracts. These coprolites have been attributed to Arthropleura. I am very fortunate in having been able to accumulate several fantastic examples of the different body structures of this amazing animal. All specimens were collected from the actual Mazon Creek site. The leg shown is also pictured in The Mazon Creek Fossil Fauna book by Jack Wittry. This first specimen is tergite which would have been positioned on the outside edge of one of the body segments. Most specimens show preserve a bumpy texture. As you can see this one is smooth and might be showing the underside of this plate.
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I have been fortunate to hunt Mazon Creek fossils for nearly 40 years. I have collected Many tens of thousands of concretions. I have also purchased premium specimens from other collectors. In the past, I have posted many of these specimens on the forum. I have decided to start posting more in depth descriptions of some of the amazing animals that can be found in the MC deposit. All specimens that I will post are from my personal collection. The first animal that I will highlight is the holothurian or sea cucumber Achistrum sp. Sea cucumbers are a common animal in today’s oceans but quite rare in the fossil record. The Marine (Essex) portion of the Mazon Creek deposit is one of the few places in the world where complete body fossils of these animals can be collected. These worm like animals are actually a type of echinoderm and show 5 radial body elements that run the length of the animal. Well preserved specimens will show a sac like body and an oral ring preserving approximately 15 calcareous plates. Occasionally the intestinal tract and other internal features will be preserved. Just like modern sea cucumbers, Achistrum sp had a leathery body covered in “J” shaped sclerites or Sigmoid hooks. Often times, detecting these under a microscope is the best way to identity poorly preserved specimens. As the animal dried out, the skin would crack and these cracks were eventually replaced by calcite. This gives the body of Achistrum sp a septarian like appearance. While modern sea cucumbers have retractable tentacles surrounding the mouth, none have been observed in Achistrum sp. The animal can reach length of over 15 centimeters however most found average under 10 centimeters. Achistrum is relatively abundant and are occasionally found in masses of multiple individuals. Despite many thousands of specimens collected, Achistrum has never been formally described. At one time it was believed that there may be as many as a dozen different species of sea cucumber found in the Mazon Creek deposit. This has been reduced to one or possibly two different types. This first image shows an exquisite specimen that I collected at Pit 11 in 2017. it is a complete animal and preserves evidence of some unusual muscular structure in the esophagus area that I have not seen before.
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