ammonites
USNM 41978, Split Mountain, Clayton Ridge, Nevada (Cambrian of the United States)

Where: Esmeralda County, Nevada (37.7° N, 117.5° W: paleocoordinates 0.9° S, 93.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Emigrant Formation, Middle Cambrian (513.0 - 501.0 Ma)

• 9.5 to 15m above base of Emigrant Formation; Amecephalus arrojosensis Biozone of lower Middle Cambrian

• group of beds-level stratigraphic resolution

Environment/lithology: offshore shelf; lithified, silty lime mudstone and lithified, concretionary lime mudstone

• interval from 9.85 to 15m above base of Emigrant Formation within a mudstone, beginning with silty limestone, ending with concretionary, bioclastic limestone

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 69437: authorized by Wolfgang Kiessling, entered by Benjamin Brenneis on 26.02.2007