ober Posted September 16, 2019 Share Posted September 16, 2019 Hello all I wonder if anyone can help me with this invert. It is from the area between Moab and I-70, in a formation identified as Mancos Shale by a former BLM paleontologist. Roadside Geology of Utah places this area as Cretaceous. The shell is 3cm long and and about 2.75cm side. The distinguishing feature is a grove running down the center on the longer dimension. There is sign of horizontal banding. I have looked in the Atlas of Cretaceous Life online, Index Fossils of No. Amer., Invertebrate Fossils by Moore et al and “Mid-Cretaceous molliscan record from west-central New Mexico. The closest pictures I find are in Invert Fossils, p 252, figure 6-34 as suborder Productacea juresania, but this item is Pennsylvanian-Permian. There are several other earlier brachiopods that look similar, but nothing cretaceous with this indent down the middle. The indent does not look like damage, but actually structural. I think, for some reason this is a mollusk, but may be wrong. I don’t know to what extent the surface of the shell was damaged in removing the overlayer. I will post another picture. Thanks for your help. Tom Link to comment Share on other sites More sharing options...
ober Posted September 16, 2019 Author Share Posted September 16, 2019 another image Link to comment Share on other sites More sharing options...
JohnBrian Posted September 17, 2019 Share Posted September 17, 2019 Kind of looks like a trilobite. But I'm frequently wrong! ---------------------------------------------------------------------------- John I had a friend once, but the wheels fell off. Sad, very sad. - Nightwing Link to comment Share on other sites More sharing options...
Shamalama Posted September 17, 2019 Share Posted September 17, 2019 Looks to me to be part of a pelecypod shell from the genus Pyncnodonte or Gryphaea . -Dave __________________________________________________ Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPheeIf I'm going to drive safely, I can't do geology. - John McPheeCheck out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/ Link to comment Share on other sites More sharing options...
FossilDAWG Posted September 17, 2019 Share Posted September 17, 2019 I agree with Dave (Shamalama). Don Link to comment Share on other sites More sharing options...
ober Posted September 17, 2019 Author Share Posted September 17, 2019 8 hours ago, Shamalama said: Looks to me to be part of a pelecypod shell from the genus Pyncnodonte or Gryphaea . Dave, thanks for this lead. I will explore this avenue. Tom Link to comment Share on other sites More sharing options...
ober Posted September 17, 2019 Author Share Posted September 17, 2019 18 hours ago, JohnBrian said: Kind of looks like a trilobite. But I'm frequently wrong! John, not a trilobite, they were extinct for more than 150 million years by the time this creature enjoyed its time in the sea. Tom Link to comment Share on other sites More sharing options...
JohnBrian Posted September 17, 2019 Share Posted September 17, 2019 19 hours ago, JohnBrian said: Kind of looks like a trilobite. But I'm frequently wrong! 1 hour ago, ober said: John, not a trilobite, they were extinct for more than 150 million years by the time this creature enjoyed its time in the sea. Tom Totally missed the part where he said it was cretaceous! Like I said above, I'm frequently wrong! But to me it looks like a piece of a trilobite covered by a thin bit of matrix. ---------------------------------------------------------------------------- John I had a friend once, but the wheels fell off. Sad, very sad. - Nightwing Link to comment Share on other sites More sharing options...
ober Posted September 17, 2019 Author Share Posted September 17, 2019 11 hours ago, Shamalama said: Looks to me to be part of a pelecypod shell from the genus Pyncnodonte or Gryphaea . Hello Dave, I can see the possibility/likelihood this falls under Gryphaea. G wratheri, Index Fossils p397 describes this fossil as clear as I’ve found, although the geographic location is further east. I don’t have an idea of its range. Thanks for your help. I am finding a world of interesting web sources and will continue to look for a good match within Gryphaea. Do you have a reference you particularly like to use in answering this type of question? Thanks. Tom Link to comment Share on other sites More sharing options...
Shamalama Posted September 18, 2019 Share Posted September 18, 2019 11 hours ago, ober said: Hello Dave, I can see the possibility/likelihood this falls under Gryphaea. G wratheri, Index Fossils p397 describes this fossil as clear as I’ve found, although the geographic location is further east. I don’t have an idea of its range. Thanks for your help. I am finding a world of interesting web sources and will continue to look for a good match within Gryphaea. Do you have a reference you particularly like to use in answering this type of question? Thanks. Tom Tom, I don't have much experience with the Mancos Shale but the shape and age made me think of those more common genera. I think you are doing the right thing by using the resources you have found and asking here. It's pretty much what I would do! -Dave __________________________________________________ Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPheeIf I'm going to drive safely, I can't do geology. - John McPheeCheck out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/ Link to comment Share on other sites More sharing options...
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