USNM 41990, Split Mountain, Clayton Ridge (Cambrian of the United States)

Where: Esmeralda County, Nevada (37.7° N, 117.5° W: paleocoordinates 1.0° S, 93.5° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Oryctocephalus indicus trilobite zone, Emigrant Formation, Delamaran (511.2 - 506.5 Ma)

• 15 to 16.6m above base of Emigrant Formation; Oryctocephalus indicus Biozone of lower Middle Cambrian

• group of beds-level stratigraphic resolution

Environment/lithology: offshore shelf; lithified lime mudstone and shale

• above 15-m horizon occurs 3-m-thick interval of dark, laminated clayshales

Size class: macrofossils

Reposited in the USNM

Primary reference: F. A. Sundberg and L.B. McCollum. 2003. Early and Mid Cambrian Trilobites from the Outer-shelf Deposits of Nevada and California, USA. Palaeontology 46(5):945-986 [W. Kiessling/B. Brenneis]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 69454: authorized by Wolfgang Kiessling, entered by Benjamin Brenneis on 26.02.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Trilobita
 Corynexochida - Oryctocephalidae
Oryctocephalus indicus, Microryctocara nevadensis
Oryctocephalus indicus Reed 1910 trilobite
total of 76 cranidia from loc. USMN 41986-41991
Microryctocara nevadensis Sundberg and McCollum 1997 trilobite
total of 81 cranidia from loc. USMN 41986-41991