Where: Howard County, Arkansas (33.8° N, 93.6° W: paleocoordinates 38.4° N, 71.2° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Nacatoch Sand Formation, Early/Lower Maastrichtian (70.6 - 66.0 Ma)

• Formation contains lower Maastrichtian Nostoceras alternatum zone ammonites elsewhere in Arkansas

• bed-level stratigraphic resolution

Environment/lithology: marine; sandstone

Size class: macrofossils

Collected by L.W. Stephenson; reposited in the USNM

Primary reference: C. W. Cooke. 1953. American Upper Cretaceous Echinoidea. United States Geological Survey Professional Paper 254-A:1-44 [W. Kiessling/U. Merkel/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 197650: authorized by Matthew Clapham, entered by Matthew Clapham on 19.11.2018

Creative Commons license: CC BY (attribution)