Where: Illinois, Iowa (42.0° N, 90.5° W: paleocoordinates 21.3° S, 63.6° W)

• coordinate estimated from map

• basin-level geographic resolution

When: Spechts Ferry Formation, Blackriveran to Blackriveran (457.3 - 449.6 Ma)

• formation-level stratigraphic resolution

Environment/lithology: pyritic, green shale

Size class: macrofossils

Collection methods: "[B]ased on a review of the Sardeson Collection at the University of Minnesota, Weiss (1953), Ulrich and Scofield (1895), the unpublished work of Levorson and Gerk, and the list in Stauffer and Thiel (1941)."

Primary reference: R. E. Sloan and G. F. Webers. 1987. Stratigraphic ranges of Middle and Late Ordovician Gastropoda and Monoplacophora of Minnesota. In R. E. Sloan (ed.), Middle and Late Ordovician lithostratigraphy and biostratigraphy of the Upper Mississippi Valley: Minnesota Geological Survey Report of Investigations 35 183-186 [S. Holland/T. Hanson/S. Bruning]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 23621: authorized by Steven Holland, entered by Tori Hanson on 17.07.2002, edited by Pete Wagner

Creative Commons license: CC BY (attribution)