Mudlark Posted May 12, 2021 Share Posted May 12, 2021 My guy found this while searching with a 365 nm uv lights for sodalite on a beach in Algoma WI. Lake Michigan. Can anyone offer a place for me to look for more information on what it could be? It is a 6 inch by 6 inch limestone rock. The object it 6 inches long and almost an inch wide. The backside of the rock has no fossil presence. The picture with the blue in the background is a 365 nm shortwave uv light. Thank you for looking 2 Link to comment Share on other sites More sharing options...
Thomas.Dodson Posted May 12, 2021 Share Posted May 12, 2021 What's the curvature like? Does it arch over the matrix? Link to comment Share on other sites More sharing options...
Mudlark Posted May 12, 2021 Author Share Posted May 12, 2021 Regular light and Uv to help define lines it shows up way better under the uv Link to comment Share on other sites More sharing options...
Lone Hunter Posted May 12, 2021 Share Posted May 12, 2021 Still hard to tell if it's curved or flat, can you get a side view in regular light from little further away? Link to comment Share on other sites More sharing options...
Mudlark Posted May 12, 2021 Author Share Posted May 12, 2021 Link to comment Share on other sites More sharing options...
Mudlark Posted May 12, 2021 Author Share Posted May 12, 2021 There are brachiopods in the matrix. And some small crinoid stems. The blank face is the back side of rock. 1 1 Link to comment Share on other sites More sharing options...
Lone Hunter Posted May 12, 2021 Share Posted May 12, 2021 That looks so cool under uv, wouldn't have thought crinoid! Link to comment Share on other sites More sharing options...
Mudlark Posted May 12, 2021 Author Share Posted May 12, 2021 Are you thinking it is a huge crinoid? There are baby ones in this picture. Someone suggested a fish spine but I know nothing about fish from this time period. I do know they find fossilized fish scales about 30 minutes west of where we found this. I am not sure which fish scales they find. Again I used UV because regular light does really illuminate the limestone better when it's beach worn. We hunt for the florescent minerals. Uv let's us see fossils we otherwise wouldn't see. 1 Link to comment Share on other sites More sharing options...
piranha Posted May 12, 2021 Share Posted May 12, 2021 The mystery specimen matches well with the siphuncle of Huronia sp. This excellent monograph has numerous species for comparison: Foerste, A.F. 1924 Silurian Cephalopods of Northern Michigan. Contributions from the Museum of Geology, University of Michigan, 2(3):19-120 PDF LINK 10 1 1 Link to comment Share on other sites More sharing options...
Rockwood Posted May 12, 2021 Share Posted May 12, 2021 I think the look fits a mold of a nautiloid shell better. Link to comment Share on other sites More sharing options...
Thomas.Dodson Posted May 12, 2021 Share Posted May 12, 2021 I feel confident calling it some straight shelled cephalopod now (I couldn't tell how flat it was which was why I asked about the curvature). I'm much less confident about weighing in on the shell mold vs. siphuncle debate. Link to comment Share on other sites More sharing options...
Rockwood Posted May 12, 2021 Share Posted May 12, 2021 24 minutes ago, Thomas.Dodson said: I feel confident calling it some straight shelled cephalopod now (I couldn't tell how flat it was which was why I asked about the curvature). I'm much less confident about weighing in on the shell mold vs. siphuncle debate. I really hadn't intended to either. My mistake. Link to comment Share on other sites More sharing options...
TqB Posted May 12, 2021 Share Posted May 12, 2021 The black light photo shows a nautiloid siphuncle beautifully, as opposed to a whole shell. 1 Tarquin Link to comment Share on other sites More sharing options...
Thomas.Dodson Posted May 12, 2021 Share Posted May 12, 2021 1 hour ago, Rockwood said: I really hadn't intended to either. My mistake. I don't think you came across that way. I was merely stating my own uncertainty. 20 minutes ago, TqB said: The black light photo shows a nautiloid siphuncle beautifully, as opposed to a whole shell. In retrospect there are gaps present in the black light photo that I wouldn't expect from a mold of a shell. Link to comment Share on other sites More sharing options...
Ludwigia Posted May 12, 2021 Share Posted May 12, 2021 I think that Piranha has hit the nail on the head once again. 4 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Rockwood Posted May 12, 2021 Share Posted May 12, 2021 2 hours ago, Thomas.Dodson said: I don't think you came across that way. I was merely stating my own uncertainty. Sorry. Only means I wasn't wrong quite right. I missed the point all together. Maybe had the general concept at least. Link to comment Share on other sites More sharing options...
Mudlark Posted May 12, 2021 Author Share Posted May 12, 2021 Thank you. I appreciate all the help. I am getting familiar with small fossils on the hash plates. Besides the large chunks of halosites we find this is one of the biggest creatures we have found so far. The uv lights really help us see things we would miss in daylight. Link to comment Share on other sites More sharing options...
FossilDAWG Posted May 12, 2021 Share Posted May 12, 2021 I'm very late to this party, as I lost use of my computer for several hours due to a misbegotten windows update that froze me out. @piranha is correct of course. I have a similar Huronia siphuncle (except not as long) from correlative Silurian rocks around Lake Temiskaming. This genus is known almost entirely from the robust siphuncles; specimens showing the rest of the shell are almost unknown. The UV light effect is remarkable! It would certainly make things much easier to spot glowing fossils at a distance. Don 2 Link to comment Share on other sites More sharing options...
Mudlark Posted May 12, 2021 Author Share Posted May 12, 2021 The Uv is pretty fascinating and helpful on fossils laying on beaches. We have found many cool fossils with it. Link to comment Share on other sites More sharing options...
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