Also From Jacksboro

[rwise]

Found this also in Finis shale of Graham formation, cisco virgilian series of upper penn, in Jacksboro, Texas,

This specimen is one inch long. Lots of Nautiloids, Conularids, brachiopods, in the area.

Any ideas??

[Uncle Siphuncle]

Michelinoceras

[Herb]

Ditto

[erose]

Guys, don't get on my case, but IMHO we have these (other post) two switched around. I think this one is either Moorecoceras or Pseudorthoceras based on the shorter chamber lengths.

What features are you basing the IDs on?

[Uncle Siphuncle]

I rely on copious amounts of "Kentucky windage" in my kneejerk IDs.

[erose]

I rely on copious amounts of "Kentucky windage" in my kneejerk IDs.

Ha ha. Everything is tentative.

I was so surprised when I first came back from Jacksboro with handfuls of these and realized there were both noticeable and subtle differences between them. I think they sorted into two large piles and a few "others". The two big piles were Moorecoceras and Pseudorthoceras based on position of siphuncle. The odd ones are still being sorted out but may require more specimens.

[Uncle Siphuncle]

in all seriousness, i don't think i've looked beyond finsley or mckinzie on id of these forms so i tend to "hogpile" these fossils into the few genera presented there for north tx without much further (yet possibly required) scrutiny.