Brewcuse Posted August 26, 2014 Share Posted August 26, 2014 When I picked this up, I thought it was a worn dipleura trilobite piece. Then, as I took a closer look, I thought "ammonoid." Closer inspection makes me think some sort of orthocone, except it's "fatter" than any I've found and not preserved "straight." Mid Devonian Upper Ludlowville Formation Hamilton Group Geer Road Quarry Madison County size 3 (narrowest) to 3.5 (widest) cm by 10 cm long I'm out of conjectures, and I'm sure someone has actual knowledge. Link to comment Share on other sites More sharing options...
BobWill Posted August 26, 2014 Share Posted August 26, 2014 Certainly nautiloid, probably cyrtoconic (some start out with loose coiling then become only slightly curved) brevicone. I don't know what's common in that formation but it looks like your internal mold includes much of the living chamber. Very nice. Link to comment Share on other sites More sharing options...
piranha Posted August 26, 2014 Share Posted August 26, 2014 Here are some possible matches from Hall 1876: Hall, J. (1876) Illustrations of Devonian fossils: Gasteropoda, Pteropoda, Cephalopoda, Crustacea and Corals of the Upper Helderberg, Hamilton and Chemung Groups. New York State Geological Survey, 236 pp. 2 Link to comment Share on other sites More sharing options...
piranha Posted August 26, 2014 Share Posted August 26, 2014 I'm not certain of the current taxonomy or synonymies of those genera. Hall's use of 'Nautilus' doesn't appear to be valid, instead Nephriticeras seems to be its replacement. Hopefully one of the NY cephalopod specialists can clarify further. 1 Link to comment Share on other sites More sharing options...
Brewcuse Posted August 26, 2014 Author Share Posted August 26, 2014 Thanks Bob and Scott… I'm always happy to find something "new" and learn more about it. Link to comment Share on other sites More sharing options...
Herb Posted August 26, 2014 Share Posted August 26, 2014 Nice specimen "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks Link to comment Share on other sites More sharing options...
howard_l Posted August 26, 2014 Share Posted August 26, 2014 There was a discussion on Devonian Nautiloids started by Fishguy back in September 2013 that might help. It has some useful publications listed. The problem with Nautiloid publications are that they don't have many current ones. Most are much older then me and I am ancient. I will be glad when they come out with a revised Treatise on Invertebrate Paleontology Part K. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
Wrangellian Posted August 27, 2014 Share Posted August 27, 2014 Nice one! Recognized it as a nautiloid right away though I don't know the finer IDs. Link to comment Share on other sites More sharing options...
Brewcuse Posted August 27, 2014 Author Share Posted August 27, 2014 Thanks Howard. I looked at that thread and found much interesting info. Considering this is the first of these I've found, I'm guessing they're not as common as the straight-shelled variety, at least in my local Central NY area, so studies of other areas are a big help. Link to comment Share on other sites More sharing options...
howard_l Posted August 27, 2014 Share Posted August 27, 2014 I am very lucky in that the lower Mississippian age units in KY have coiled nautiloids in some areas more common than the straight ones. From what I have seen found the straight nautiloids are very similar to the Devonian of New York as far as some genus, they both have Michelinoceras and spyroceras. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
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