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Showing results for tags 'chaetetid'.
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Wilco65 posted a topic in Fossil IDI found this along the Fox River in Elgin, IL. At first I thought it was a stromatoporoid fossil (I find them everywhere in this area), but upon closer inspection I couldn't see anything that looked like pillars or laminae. Someone suggested chaetetid sponge, or a stromatoporoid that was distorted by silicification. I can't find any photos that look like my spec. except dino bone and we don't have those in northern Illinois. Is it a natural formation, crazy looking oolites? I'm totally stumped! More pics
RTR227 posted a topic in Fossil IDThis is my first post in Fossil Forum...names PD, in the next couple of days I will do an introductory post in the "Introduction" section but I wanted to get started with one of my specimens that has brought me to a wall. Late Devonian - Early Carboniferous, loose find in a fossil contaminated area so identifying the exact formation it came from has been a bit difficult. Possibilities within a stones throw of find are Boone Formation, Penters Chert, Clifty Limestone, Chattanooga Shale and Pitkin Limestone. I have been calling this little guy Tholuslensia collisspongia ONLY until I can identify the actual genus and species. From my current research, I have an initial taxonomy as follows: Porifera | Demospongiae | Chaetetid | Poecilosclerida | AND THAT IS WHERE MY GIANT WALL BEGINS... As you might already be aware, Arkansas does not have a good public fossil record database (something that I am currently working on changing) and trying to identify this sponge down through family, genus and species has been like trying to find the pin cushion that the needle in the haystack came out of. The University of Arkansas focuses more on fossil fuels than actual fossils, they were quite friendly but unable to provide me with any assistance. Their Museum Collection is off limits to me because I am not a paleontologist, accredited institution or research facility. Even though I am not a paleontologist, I do believe myself capable of figuring this puzzle out. It is just one of many paleontology puzzles I am currently working on. I am not afraid of rabbit holes, big words or old paleontology text books so if you have any information or leads that can help me get past this "wall" then by all means, SHARE ;-). There is a possibility that it could have come out of the Ordovician period. The majority of exposure, sediment and specimens from this location are Devonian/Mississippian. There is one new exposure of Ordovician that has surfaced due to creek erosion. It rests below all other primary material and my collisspongia could have eroded out of that exposure based on sheer proximity to the specimens resting location. I have my doubts though because of the iron staining that has permeated the calcified sandstone.Based on the amount of orange tinting the outer surface displays, I would think that the specimen had to have eroded out and been sitting for some time now. New fractures from the Ordovician peek-a-boo seem to be lighter in color ranging from white to camel tan. This orange tint makes me believe that the Ordovician formation is not the host rock that produced my fossil. That being said, I am perfectly comfortable with the idea and most likely, the actuality of being completely and totally WRONG about everything. So long as I can get close to the truth, I am good with as many missteps as it will take. Thanks again for anything you have to offer and thank you for helping create this great resource and forum. Specifications: Length (Middle Lens Curve): 110 mm Width (Across Lens Curve): 100 mm Height (Stem to Top of Dome): 70mm Circumference (Lens Perimeter): 340 mm Substance: White chert, calcified sandstone, limestone present within folds and around bottom stem/base
I've always been fascinated with the chaetetid sponge reefs that dominate the limestone beds of the Pennsylvanian Marmaton Group. Since these strata outcrop thirty to fifty miles east of the Kansas City metro, I don't have many opportunities to find them. This weekend, we drove out to a family event in southeast Missouri. I took the opportunity to check out a road cut in the Pawnee Formation near Holden, Missouri that I had read about in a publication. The chaetetids are present in the Coal City Limestone member of the Pawnee. At the expected spot, I encountered the black Anna Shale and a thick limestone that could be the Coal City: The limestone was basically barren. When I stepped back, I noticed that there are actually two limestones in the cut: Yeah, now I remember. The lower ledge is the Myrick Station Limestone. The one I'm looking for is on top. Up close, it appears to be an impenetrable wall. No fossils could be seen on the weathered joint surface or in the rubble: