Mike Pocock Posted October 20, 2014 Share Posted October 20, 2014 Hi I found this piece of rock when i was in Kentucky in July this year, It was dumped at the side of the road so its not from the local area, the matrix is very fragile and crumbles, and is greenish in colour. (I think it looks like egg shell, but that may be wishful thinking) Lots of other fragments are present in the rock but are difficult to uncover as they just shatter or crumble. Any help would be appreciated Regards Mike Link to comment Share on other sites More sharing options...
Raggedy Man Posted October 20, 2014 Share Posted October 20, 2014 (edited) Looks like a crinoid caylx EDIT: Not to sure about the specific species, but it does resemble the ones I found in St.Paul, Indiana. I have a few pictures in the fossil hunting trip section listed under two from st.paul. Those cayli...are Eucalyptocrinites crassus. I hope this helps! Best regards, Paul Edited October 20, 2014 by Raggedy Man ...I'm back. Link to comment Share on other sites More sharing options...
Xiphactinus Posted October 20, 2014 Share Posted October 20, 2014 Hi Mike. It's not eggshell. The area is all wrong (Kentucky is primarily Paleozoic marine). Also, the thickness of the "shell" is very irregular. If it was an eggshell, it would be consistent. So much for the what it's not. Now the, "what is it then"? I'm leaning towards a mineral deposit. It COULD be a shell fragment from a large sea creature such as an ammonite, but again the variable thickness leads me away from that and back to mineral. We'll have to see what some others say..... Link to comment Share on other sites More sharing options...
tmaier Posted October 20, 2014 Share Posted October 20, 2014 To figure out if this is just a mineral deposit or a fossil, you need to find features. I've scanned the photos pretty carefully and can't find anything to point at. For example, if it was a crinoid calyx (which it does look like from afar), then it should be composed of plates that should show joints. I'm not sure if I'm seeing them. There are a lot of cracks that are random, but the calyx would have a regular geometry to the plates. So my opinion is that it is most likely a fossil something, but lacks definitive diagnostic features. Link to comment Share on other sites More sharing options...
Taogan Posted October 20, 2014 Share Posted October 20, 2014 I've looked for structures, but can't see any either, I would guess mineral. Link to comment Share on other sites More sharing options...
howard_l Posted October 20, 2014 Share Posted October 20, 2014 Yes it is an echinoid of some type probably crinoid, it looks like Mississippian but if you tell me what area I can tell you for sure. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
Xiphactinus Posted October 20, 2014 Share Posted October 20, 2014 (edited) howard - What makes you say that? I don't see any indication of plates or 5-fold symmetry. I see lots of cracks.... Edited October 20, 2014 by Xiphactinus Link to comment Share on other sites More sharing options...
Al Dente Posted October 20, 2014 Share Posted October 20, 2014 When echinoderm plates fossilize, the calcite that fills the pore space grows as a single crystal. As a result, when fossil echinoderms fracture they do so in the same way a calcite crystal will. They will break into rhomb shaped pieces. You can see this in the photos of this fossil. I think it is part of a crinoid calyx. Link to comment Share on other sites More sharing options...
howard_l Posted October 20, 2014 Share Posted October 20, 2014 I have seen specimens like this numerous times in the Mississippian of Kentucky and especially in the Nada Member of the Borden. If you look very closely at the second picture you can see crinoid plates that are partially covered by debris. When echinoids break they display a fracture as seen in these pictures. In some cases you may have to etch the material with a weak acid to define the plates so they can be seen. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
tmaier Posted October 20, 2014 Share Posted October 20, 2014 If you look very closely at the second picture you can see crinoid plates that are partially covered by debris. Link to comment Share on other sites More sharing options...
ashcraft Posted October 21, 2014 Share Posted October 21, 2014 That would be one big calyx by where I live. Brent Ashcraft ashcraft, brent allen Link to comment Share on other sites More sharing options...
howard_l Posted October 21, 2014 Share Posted October 21, 2014 I found a calyx on Lake Cumberland that was as big as my fist. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
ashcraft Posted October 21, 2014 Share Posted October 21, 2014 I found a calyx on Lake Cumberland that was as big as my fist. Don't want to hijack a thread, but I would love to see that. Brent Ashcraft ashcraft, brent allen Link to comment Share on other sites More sharing options...
howard_l Posted October 21, 2014 Share Posted October 21, 2014 It is hard to tell but it looks like a brachiopod encrusted with fenestrate bryozoan on it. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
howard_l Posted October 21, 2014 Share Posted October 21, 2014 (edited) Ashcraft, the crinoid I mentioned is in my gallery. I think #166 Edited October 21, 2014 by howard_l Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
ashcraft Posted October 22, 2014 Share Posted October 22, 2014 Ashcraft, the crinoid I mentioned is in my gallery. I think #166 What a beast. Brent Ashcraft ashcraft, brent allen Link to comment Share on other sites More sharing options...
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