Kasimovian Goniatitid

[cngodles]

I've had this for quite some time, I thought it may have been a gastropod. But I'm now very convinced I have an ammonoid.

 

They are very rare over my way, they didn't like coming into the geologically temporary shallow sea bays that formed. We have many Nautiloids, but not many Goniatitids. I've considered Pennoceras and Mangeroceras. The former is reported from rocks of similar age in Ohio, but the shell ornament has me considering the latter. The growth lines curve back towards the posterior at the dorsal-lateral shoulders. Anyone from the mid-continent (who are swimming in ammonoids at places) have a good ID for this one?

 

Scale bar = 5 mm.

Conemaugh Group

Glenshaw Formation

Brush Creek limestone

 

[cngodles]

After much reflection, I'm well set on Pennoceras.