Where: Larimer County, Colorado (40.5° N, 105.1° W: paleocoordinates 46.9° N, 74.5° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Larimer Sandstone Member (Pierre Shale Formation), Late/Upper Campanian (83.5 - 70.6 Ma)

• "Horizon is 60 feet above the base of the sandstone member of the Pierre Shale that makes Fossil Ridge. There is some difference of opinion as to the name of the sandstone member. Some earlier workers thought that it belonged to the Larimer Member, but later opinion assigns it to the Rocky Ridge member." Kennedy et al. (2000) assign collections in the Fossil Ridge area to the Larimer Sandstone member of Late Campanian age.

• group of beds-level stratigraphic resolution

Environment/lithology: offshore; poorly lithified, concretionary sandstone

Size class: macrofossils

Collected by D.V. Harris; reposited in the USNM

Primary reference: J. B. Reeside and D. V. Harris. 1952. A Cretaceous horseshoe crab from Colorado. Journal of the Washington Academy of Science 42:174-178 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 216750: authorized by Matthew Clapham, entered by Matthew Clapham on 23.12.2020

Creative Commons license: CC BY (attribution)