ammonites
Quimbys Mill Formation Bryozoans of the Upper Mississippi Valley (Ordovician of the United States)

Where: Wisconsin, Illinois, Iowa (42.5° N, 91.3° W: paleocoordinates 20.6° S, 63.7° W)

• coordinate estimated from map

• basin-level geographic resolution

When: Quimbys Mill Formation, Rocklandian (460.9 - 449.5 Ma)

• formation-level stratigraphic resolution

Environment/lithology: limestone and dolomite

• Environmental call by T. Hanson.
• "12 to 14 feet thick . . . medium to thin beds of limestone and dolomite separated by thin shale laminae."

Size class: macrofossils

Primary reference: O. L. Karklins. 1987. Bryozoa from Rocklandian (Middle Ordovician) rocks of the Upper Mississippi Valley region. Middle and Late Ordovician lithostratigraphy and biostratigraphy of the Upper Mississippi Valley: Minnesota Geological Survey Report of Investigations 35 173-176 [S. Holland/T. Hanson/T. Hanson] more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 23305: authorized by Steven Holland, entered by Tori Hanson on 11.07.2002