ammonites
Grand Detour Formation Gastropoda and Monoplacophora, Illinois and Iowa (Ordovician of the United States)

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: Grand Detour Formation, Blackriveran (460.9 - 449.5 Ma)

• formation-level stratigraphic resolution

Environment/lithology: limestone

• Lithology and environment taken from Kolata, D. R. "Lithostratigraphy of the Plateville, Galena and Maquoketa Groups in Northern Illinois." Middle and Late Ordovician Lithostratigraphy and Biostratigraphy of the Upper Mississippi Valley: Minnesota Geological Survey Report of Investigations 35, p. 21-24. R. E. Sloan, ed.

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on a review of the Sardeson Collection at the University of Minnesota, Weiss (1953), Ulrich and Scofield (1895), the unpublished work of Levorson and Gerk, and the list in Stauffer and Thiel (1941)."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. 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/T. Hanson] more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 23617: authorized by Steven Holland, entered by Tori Hanson on 17.07.2002, edited by Pete Wagner