Ammonites from the
Prionocyclus macombi Meek 1876
Prionocyclus cf. P. macombi
These ammonites came from a concretion in the middle of the Juana Lopez
Member of the Mancos Shale
(the top of the lower questa) about 10 meters below the concretions
with typical P. macombi.
the one on the left is 33mm dia.
They seem closer to P. hyatti than P. macombi, they
have a larger umbilicus and two rows of ventro-lateral tubercles on
stronger ribs. However one of the distinguishing features of P.
macombi are the fine ribs on the juvenile shells.
Coilopoceras inflatum Cobban and Hook 1980
a small specimen 68mm
a large adult 533mm
From concretions in the Juana Lopez Member south of Price.
carlislensis Morrow 1935
The only specimen of Scaphites I have found from this biozone
44mm long, from the Juana Lopez Member southeast of Green River.