ammonite from mancos shale utal

[ober]

Hello all,

 

I thought this would be a fairly easy identification, given the distinct deep indentations in the ridge of this ammonite fragment. I looked in Fossil Index of NA, Invertebrate Fossils by Moore et al, a  Collignoniceras survey and the Atlas of Cretaceous Life, online. This fragment comes from Mancos Shale near Moab, Utah. Help appreciated. And if you can suggest sources for this era and region I’d appreciate it. Thanks.

 

Tom

 

 

[PFOOLEY]

I think it would be difficult to identify this piece beyond "ammonite impression". The Mancos timeline is vast and within it, the Collignoniceratids evolve from Collignoniceras to Prionocyclus to Forresteria...all of which would leave a similar impression. You might have better luck with finding an i.d. if you could determine from which member of the Mancos the specimen was recovered.