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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.
ziggycardon posted a topic in Micro-paleontologyHi everyone I think I just found a new hobby With my latest fossil delivery I recieved quite a lot of microfossils & matrix vials as the world of microfossils was something that I have been long interested in. So a 2 weeks ago I finally ordered my first microfossils for which I reserved a special drawer in my archive cabinet. So here is a recapp of what I all got: 3 vials of permian material from Waurika, Oklahoma 1 vial of permian material from The red beds of Archer County, Texas 1 small vial of Conodont rich Mississippian material from the Chappel Limestone formation, Texas 1 small vial of Cretaceous Lower Gault Clay, East Wear bay, Folkestone, Kent, UK A micropalaeontology slide with Jurassic Blue Lias matrix rich in holothurian material. A thin section of an Ostracods filled Elimia snail from the Green River Formation in Wyoming A thin section from the Rhynie chert of Scotland which should contain preserved parts of the plant Aglaophyton major and perhaps even other species. I also got a lot of Bull Canyon micro fossil teeth and 2 cretaceous mammal teeth from Hell Creek In this topic you will be able to follow my path through this newly discovered hobby as I will post my finds and progress Currently I am only working with a clip-on cellphone microscope, but I do plan on getting a professional microscope in the next few months! (Tips are always welcome) So let's put on our Ant-Man suit and explore the microfossil realm So here are some of the first pictures I made of some of the microfossils Starting with the thin slices! Thin slice with Ostracon filled Elimia tenara snail from the Green River Formation, Wyoming Thin slice with Aglaophyton major from Rhynie Chert in Scotland