Trilobites of the Pentagon Shale Formation


Northwestern Montana

Pentagon Shale - Two localities: Pentagon Mountain and Lick Creek-Continental Divide - Deiss 1936



Agnostus brevispinus
Agnostus robustus
Bathyuriscus haydeni
Meek, 1873[= Bathyuriscus formosis Deiss, 1939 (fida Robison, 1964)]
Ehmaniella concava
(formerly Clappaspis concava)
Ehmaniella  convexa
(formerly Clappaspis convexa)
Ehmaniella  hebetis
(formerly Clappaspis hebetis)
Ehmaniella  lickensis
(formerly Clappaspis lickensis)
Ehmaniella  mcnairi
(formerly Clappaspis mcnairi)
Ehmaniella  obscura
(formerly Clappaspis obscura)

Ehmaniella ornatus (formerly Anomalocephalus ornatus)
Ehmaniella  papulata
(formerly Clappaspis papulata)
Ehmaniella  singularis
(formerly Clappaspis singularis)
Ehmaniella  striata
(formerly Clappaspis striata)
Ehmaniella  typica
(formerly Clappaspis typica)
Ehmania convexa
Ehmania elongata
Ehmania exilis
Ehmania incerta
Ehmania perfecta
Ehmania sulcata
Ehmania unispinata
Elrathiella convexa
Elrathiella crassiorata
Elrathiella manifesta
Elrathiella nitida
Elrathiella plana
Elrathiella recta
Elrathiella sulcata
Elrathiella tenuis
Elrathiella unisulcata
Elrathiella valens
Kootenia pariquadriceps
Kootenia serrata
Kootenia subequalis
Parehmania arcuata
Parehmania concava

Parehmania cylindrica (formerly Rowia cylindrica)

Parehmania delicata (formerly Rowia delicata)

Parehmania granulata (formerly Rowia granulata)
Parehmania princeps
Parehmania quadrata
Parehmania storeyi

Parehmania vulgata(formerly Rowia vulgata)

Ptychoparella convexa (formerly Elrathina convexa)
Ptychoparella fecunda 
(formerly Elrathina fecunda)
Ptychoparella oculineata 
(formerly Elrathina oculineata)




Deiss,Charles (1939) Cambrian Stratigraphy and Trilobites of Northwestern Montana. The Geological Society of America, Special Papers, Number 18


Resser, C.E. (1935) Nomenclature of some Cambrian Trilobites, Smithsonian, Misc. Coll.., Vol. 93, No. 5, P. 1-46

* Researched and Compiled by George Ast


Western Trilobites Association Home:
Trilobite Genera / Species I Trilobite Formations I Trilobite Locations