phhill18 Posted December 16, 2020 Share Posted December 16, 2020 Hi there - Been following this forum for years now but this is my first time posting! Figured I should finally try to figure out what this mystery fossil is that I have... Years ago - probably 10 years ago at this point - I found this fossil washed up on the beach at Bald Head Island NC. Because of its markings, I assumed it was likely a nautilus, but everything I found online or in fossil books of NC looked dissimilar from this particular piece. So, I'll ask you all - what do you think it is? Am I right to think it's a nautilus of some kind, or perhaps something else? Thank you so much! 1 Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted December 16, 2020 Share Posted December 16, 2020 Yes, I would say that's a nautiloid, I think Eutrephoceras is found in those parts. Hello, and a very warm welcome to TFF from Morocco. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
hemipristis Posted December 16, 2020 Share Posted December 16, 2020 I agree with Tigby. It's a nautiloid. I've found several Eutrephoceras nautiloids in the Carolinas, but they were always stinkerns. Never saw ribs or ornamentation. The little hole in the shell that exposes the interior reminds me of them. Nice 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
Plax Posted December 16, 2020 Share Posted December 16, 2020 Can't say why exactly, but this doesn't look like Eutrephoceras which we have from late cretaceous Peedee to middle eocene Castle Hayne Formation. Am thinking it may be something from the Bald Head Shoals formation (Paleocene) which is only found in cores and a few spoil islands in the Cape Fear River. Link to comment Share on other sites More sharing options...
LabRatKing Posted December 16, 2020 Share Posted December 16, 2020 Fairly certain this is Eutrephoceras carolinensis with a bit of erosion. Somewhere around here I have a box with a few I collected down there in my active duty days. One of them is very similar to this one. I will have to see If I can dig out that box from the mess to confirm. This is an uneroded grab from the web: Link to comment Share on other sites More sharing options...
Al Dente Posted December 16, 2020 Share Posted December 16, 2020 It's not Eutrephoceras. The siphuncle is in the wrong position and the septa curve in the wrong direction for almost all coiled nautiloids. It could be a very worn ammonite with most of the sutures worn off and a marginal siphuncle from the inner whorl or it might be a partial Aturia nautiloid with most of the outer whorl missing. Here's a picture of Eutrephoceras showing the siphuncle and a comparison with Aturia. 6 Link to comment Share on other sites More sharing options...
LabRatKing Posted December 16, 2020 Share Posted December 16, 2020 cool! Learn something everyday round here! Link to comment Share on other sites More sharing options...
phhill18 Posted December 16, 2020 Author Share Posted December 16, 2020 24 minutes ago, Al Dente said: It's not Eutrephoceras. The siphuncle is in the wrong position and the septa curve in the wrong direction for almost all coiled nautiloids. It could be a very worn ammonite with most of the sutures worn off and a marginal siphuncle from the inner whorl or it might be a partial Aturia nautiloid with most of the outer whorl missing. Here's a picture of Eutrephoceras showing the siphuncle and a comparison with Aturia. Thank you everyone for all the responses! This has baffled me for years because it didn't seem quite as round as Eutrephoceras...it seems like it has to be Aturia nautiloid, as you've indicated here. Thank you for your insight and I really appreciate you helping me solve this mystery! Link to comment Share on other sites More sharing options...
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