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Linda Lewis posted a new specimen. 6 years, 7 months ago
6 years, 7 months ago6 years, 7 months agoLinda Lewis has contributed specimen mFeM 52764 to myFOSSIL!
Linda Lewis posted a new specimen. 6 years, 7 months ago
Linda Lewis has contributed specimen mFeM 52764 to myFOSSIL!
Hi, @linda-lewis – I’m not super familiar with the area but maybe @nathan-newell, a more local expert, could help you fill in some of the gaps on your dataset.
@linda-lewis Hi, Linda! This is a curious find because the rocks in that area are primarily Tertiary in age, and I don’t think that horn corals survived until then. Are you sure you didn’t find this somewhere more towards the mountains?
Regardless, thanks for posting it. The details on this specimen look really cool. 🙂
To me the coral looked scleractinian but I was afraid to say it! The way the septae (spokes on the wagon wheel) are different in rugose v scleractinia. I can’t find anything at the moment to support this but I want to say it has to do with the number 6 in scleractinia and rugose is 4 or something crazy like that. Maybe @mackenzie-smith remembers…
I’m flipping though my handy dandy Audubon fossil field guide, and the Parasmilia looks really similar to this. What do you think?
I agree it looks really similar and is totally a possibility!
@linda-lewis @jbauer Yes, there are solitary scleractinians. I think the easiest way to tell them apart is to look at their septal symmetry (here is an example https://ucmp.berkeley.edu/cnidaria/anthozoamm.html). Rugose are bilateral and scleractinians have hexagonal symmetry. To me, the specimen looks more bilateral but that could be because of weathering on the specimen or the angle I’m looking at. @nathan-newell from your knowledge of the area, is it possible that this specimen was transported by a creek from an older site?
I was trying to remember the symmetry but I think it goes deeper into the pattern of septae too. There is something very different about rugose. There is also a pattern in the exterior growth that I don’t see here, but am not sure how to verbally define. Thanks for chiming in @mackenzie-smith! Always good to get another set of eyes on these =]
It’s possible, but I’d say it’s unlikely. Montross is right between the Rappahannock and Potomac rivers, both of which are pretty much all Cenozoic until 40-50 miles upstream. And neither river is a straight-shot to the ocean; the Potomac in particular has lots of snakey curves that I would think would catch fossils tumbling along in the current.