Ammonites from the
Prionocyclus macombi
Biozone




Prionocyclus macombi  Meek 1876

  pmac pmacombi
gracile form of Prionocyclus macombi from the upper part of the Juana Lopez Member of the Mancos Shale
Southeast of Green River, Utah.  The one on the left is 52mm and the one on the right is 92mm


macombir Pmacombi

robust form of Prionocyclus macombi, left 109mm, right 130mm


Pmac  
 
robust form of Prionocyclus macombi 90mm.  showing sutures.  from the same locality as those above.

large P. macombi

a large adult specimen from concretions in the Juana Lopez Member south of Price.
335 mm dia., the gracile form.




Prionocyclus cf. P. macombi

cfhyatti  
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

C. inflatum
a small specimen 68mm

Large P macombi
a large adult 533mm
From concretions in the Juana Lopez Member south of Price.



Scaphites carlislensis Morrow 1935


Scaphites carlislensis

The only specimen of Scaphites I have found from this biozone in Utah,
44mm long, from the Juana Lopez Member southeast of Green River.


<back to Hyatti Zone | Home Chart| on to Wyomingensis Zone>