iTeachMiddleSchool Posted February 19, 2018 Share Posted February 19, 2018 Sorry for the shadow/light. The whole fossil is about an inch long. Is that the foot sticking out at top left? Or do you think it's just that the rest of the shell was broken off and never became part of the fossil? It's very soft mudstone (can scratch it with my fingernail), but I know soft parts don't tend to get preserved. This is another beach fossil, so I don't know anything about the age. Link to comment Share on other sites More sharing options...
iTeachMiddleSchool Posted February 19, 2018 Author Share Posted February 19, 2018 (edited) Here's a better closeup. Edited February 19, 2018 by iTeachMiddleSchool Link to comment Share on other sites More sharing options...
ynot Posted February 19, 2018 Share Posted February 19, 2018 I think it is 2 pieces of different shells that just happen to be laying together in the rock. Soft body parts would not be preserved in a rock of this type. 1 Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Heteromorph Posted February 19, 2018 Share Posted February 19, 2018 To me it looks like part the shell was broken off leaving part of it sticking out. It all looks like the same shell with just some of it missing. 4 Link to comment Share on other sites More sharing options...
abyssunder Posted February 19, 2018 Share Posted February 19, 2018 I suppose it is a partial brachiopod on the crinoidal matrix, similar to Rafinesquina. 2 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted February 19, 2018 Share Posted February 19, 2018 I agree it's all part of the shell of one much bigger brachiopod, you can see the ribs continue from the different coloured piece into the main part. Pretty sure it's a strophomenid. Nice find! 2 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
Peat Burns Posted February 19, 2018 Share Posted February 19, 2018 34 minutes ago, abyssunder said: I suppose it is a partial brachiopod on the crinoidal matrix, similar to Rafinesquina. I agree. This looks like a single broken brachiopod. Given location it might be Devonian. If so, possibly Protoleptostrophia perplana. The hinge is mostly complete, but most of the margins and commissure are missing. What's odd is the apparent lack of a broken edge (?) on the "projecting" part. It almost looks folded under. Perhaps an epizoan encrustation? Abraded / worn? EDIT: looking more closely at all the photos, the edge does appear broken and not worn. The last photo was throwing me off. 2 Link to comment Share on other sites More sharing options...
iTeachMiddleSchool Posted February 19, 2018 Author Share Posted February 19, 2018 Yeah, the closer I look the more clear it is that the rays continue through the part that sticks out. Really glad I got my self a 25x loupe! Ok, so something like Rafinesqina? Thanks. So that would put the age at Ordovician - Carboniferous? Related question: how/where can I find information about the types/ages of rocks and fossils I am likely to find on my local Lake Michigan beach? Do you have favorite online geology resources, or a preferred book? Link to comment Share on other sites More sharing options...
Monica Posted February 19, 2018 Share Posted February 19, 2018 Maybe the geological maps above can help? They're from https://wgnhs.uwex.edu/wisconsin-geology/bedrock-geology/ Welcome to the forum from a fellow teacher!!! Monica PS - I changed the geological map because I thought you were from Michigan, but then I read that you're on Lake Michigan, but from Milwaukee, Wisconsin - sorry about that!!! So perhaps the bedrock in your area is Silurian or Devonian? 4 Link to comment Share on other sites More sharing options...
Peat Burns Posted February 19, 2018 Share Posted February 19, 2018 9 minutes ago, iTeachMiddleSchool said: Yeah, the closer I look the more clear it is that the rays continue through the part that sticks out. Really glad I got my self a 25x loupe! Ok, so something like Rafinesqina? Thanks. So that would put the age at Ordovician - Carboniferous? Related question: how/where can I find information about the types/ages of rocks and fossils I am likely to find on my local Lake Michigan beach? Do you have favorite online geology resources, or a preferred book? Being from Michigan, it has likely been transported by glaciers. Michigan has a relatively diverse bedrock geology, including rocks from many periods in the paleozoic, so the rock from which it originated could be from one of several time periods. If we can get a positive ID on the brachiopod or any other fossils in the rock, that will give us a solid clue on relative age / time period. Looking more closely at the photos and the abundance of crinoids, I'm almost getting a Mississipian vibe. But it's just a vibe 3 Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted February 19, 2018 Share Posted February 19, 2018 6 minutes ago, Peat Burns said: Being from Michigan, it has likely been transported by glaciers. Michigan has a relatively diverse bedrock geology, including rocks from many periods in the paleozoic, so the rock from which it originated could be from one of several time periods. If we can get a positive ID on the brachiopod or any other fossils in the rock, that will give us a solid clue on relative age / time period. Looking more closely at the photos and the abundance of crinoids, I'm almost getting a Mississipian vibe. But it's just a vibe Agreed, it looks Mississippian or maybe Devonian to me. 1 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
iTeachMiddleSchool Posted February 19, 2018 Author Share Posted February 19, 2018 (edited) About the crinoids - which crinoids have a star-shaped hole in the middle? I see a star shape in almost every single one. Is that an identifiable type? I thought they were sand dollars. Edit: a quick note: it's from Lake Michigan, a beach near Milwaukee. not from the state of Michigan. But still a glaciated area, so, everything said above still applies. Edited February 19, 2018 by iTeachMiddleSchool Link to comment Share on other sites More sharing options...
Kane Posted February 19, 2018 Share Posted February 19, 2018 There are quite a few species of crinoids that have star-shaped lumen, and so it is not such an easy feat to identify crinoids by their ossicles alone. In your picture above, I see three distinct star-shaped lumen, each possibly belonging to a separate species. It is definitely much easier to identify them by their calyx, if possible. Without knowing its exact provenance, identification is a major challenge! 5 ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
abyssunder Posted February 20, 2018 Share Posted February 20, 2018 I agree with Kane. They look very close to Floricyclus columnals. 2 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
iTeachMiddleSchool Posted February 21, 2018 Author Share Posted February 21, 2018 This is really helping me get an idea what to look for on my next beach trip! This is so much fun. so i’ve been using a dremel tool to clean around things. Anyone think it’s worthwhile to try to excavate one of these tiny crinoid stalks? Or if it was you, would you just spend your time looking for better fossils? Link to comment Share on other sites More sharing options...
Kane Posted February 21, 2018 Share Posted February 21, 2018 If it were me, I would leave the crinoid bits in their context. However, they are incredibly abundant in many places I collect, in some areas weathering out entirely. Regardless of my choice to remove or leave well enough alone, looking for more fossils is a given. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
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