ammonites
Decorah Shale Gastropoda and Monoplacophora, Minnesota (Ordovician to of the United States)

Where: Minnesota (46.0° N, 94.0° W: paleocoordinates 16.8° S, 62.3° W)

• coordinate estimated from map

• basin-level geographic resolution

When: Decorah Shale Formation, Rocklandian to Rocklandian (460.9 - 449.5 Ma)

• formation-level stratigraphic resolution

Environment/lithology: gray shale

• Environmental call by T. Hanson
• "[G]reenish-gray to pale-olive fossiliferous shale or claystone with lenses and think beds of coquinoidal limestone and calcareous shale." W. F. Rice. 1987. The systematics and biostratigraphy of the Brachiopoda of the Decorah Shale at St. Paul, Minnesota. Middle and Late Ordovician lithostratigraphy and biostratigraphy of the Upper Mississippi Valley: Minnesota Geological Survey Report of Investigations 35 :136-166. R. E. Sloan, editor.

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on a review of the Sardeson Collection at the University of Minnesota, Weiss (1953), Ulrich and Scofield (1895), the unpublished work of Levorson and Gerk, and the list in Stauffer and Thiel (1941)."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 23558: authorized by Steven Holland, entered by Tori Hanson on 16.07.2002, edited by Pete Wagner