Trilobites of the Emigrant Formation


Emigrant Formation, southern Great Basin (western Nevada):


Amecephalus arrojosensis (Lochman, 1952)
Bolbolenellus brevispinus Palmer, 1998

Crassifimbra walcotti (Resser, 1937)

Eokochaspis delamarensis? Sundberg and McCollum, 2000
Eokochaspis longspina? Sundberg and McCollum, 2000

Eokochaspis nodosa  Sundberg and McCollum, 2000
Eokochaspis piochensis? (Palmer, in Palmer & Halley, 1979)
Mexicella robusta 
Sundberg and McCollum, 2000

Microryctocara nevadensis Sundberg and McCollum, 1997
Olenellus sp.

Onchocephalites claytonensis Sundberg & McCollum, 2003b
Onchocephalites sp. Sundberg & McCollum, 2003b
"Onchocephalus"  cf.  maior  Rasetti, 1951

Oryctocephalites runcinatus Shergold, 1969

Oryctocephalus americanus Sundberg & McCollum, 2003b - see Oryctocephalus americanus (Sundberg 2003) [Monola Formation]

Oryctocephalus indicus (Reed, 1910)
Oryctocephalites orientalis Saito, 1934
- see Oryctocephalites orientalis [Monola Formation]
Oryctocephalus sp. A
Ovatoryctocara? sp.
Paraantagmus latus Yuan & Li, 1999
Syspacephalus cf. laticeps  Rasetti, 1951

Syspacephalus variosus Sundberg & McCollum, 2003b

Tonopahella goldfieldensis  Sundberg & McCollum, 2003b

Wenkcheminia sulcata Rasetti, 1951
Wenkcheminia walcotti Rasetti, 1951
kochaspid sp.
ptychopariid sp. A


New Fauna:


    These trilobites from the Goldfield Hills are reported to be from the Emigrant Fm. (Pioche equivalent), but they are Upper Cambrian in age. We're not sure whether the strata is correctly identified, as all Emigrant species we know of are Lower and Middle Cambrian.

    Fred Sundberg identified the species as most likely being conspecific with ones found in the McKay Group of British Columbia ("Upper Steptoean (Upper Cambrian) trilobites from the McKay Group of Southeastern British Columbia, Canada" by Brian Chatterton and Rolf Ludvigsen, 1998, JP Memoir 49). These are most likely the first reported trilobites of the Elvinia Biozone, Steptoean Stage (other than a very simple, very small elviniid that Dr. Sundberg found at Goldfield in limestones) in this area. This rock unit would be equivalent with a portion of the Halfpint Member, Nopah Formation, of Nevada.  This is the first time that the two ptychopariids have been reported from the southwestern US.


cf. Labiostria westropi Chatterton and Ludvigsen, 1998

cf. Pseudagnostus communis Hall and Whitfield, 1877

cf. Wujiajiania sutherlandi Chatterton and Ludvigsen, 1998





Chatterton, B. D. E. and Ludvigsen, R. (1998)  Upper Steptoean (Upper Cambrian) trilobites from the McKay Group of southeastern British Columbia, Canada. The Paleontological Society, Memoir 49, Journal of Paleontology, Vol. 72, March, 1998, Supplement to No. 2, 43 pp.


Sundberg, F.A., and McCollum, L. B. 2003b, Early and Mid Cambrian trilobites from the outer-shelf deposits of Nevada and California, USA. Palaeontology, v. 46, part 5, p. 945-986.


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