ammonites
Spechts Ferry Formation Echinoderms, Upper Mississippi Valley (Ordovician to 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: Spechts Ferry Formation, Blackriveran to Blackriveran (460.9 - 449.5 Ma)

• formation-level stratigraphic resolution

Environment/lithology: pyritic, green shale

• Environmental call by T. Hanson.
• "[D]ark-green to green-gray, thin-bedded, soft, locally pyritic shale interbedded with fine- to medium-grained argillaceous limestone." Lithology from 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. R. E. Sloan, ed.

Size class: macrofossils

Primary reference: D. R. Kolata, J. C. Brower, and T. J. Frest. 1987. Upper Mississippi Valley Champlainian and Cincinnatian echinoderms. Middle and Late Ordovician lithostratigraphy and biostratigraphy of the Upper Mississippi Valley: Minnesota Geological Survey Report of Investigations 35 179-181 [S. Holland/T. Hanson/T. Hanson] more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 23454: authorized by Steven Holland, entered by Tori Hanson on 15.07.2002