Amoco Production Co. Richter #1 - North Dakota Geo Survey Well #7340 (Ordovician of the United States)

Where: North Dakota (46.9° N, 101.7° W: paleocoordinates 11.5° S, 62.1° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Gunn Member (Stony Mountain Formation), Richmondian (449.6 - 445.5 Ma)

• member-level stratigraphic resolution

Environment/lithology: deep subtidal; lithified, shelly/skeletal packstone and lithified, gray, calcareous shale

• environment based on type section of Gunn Member north of Stony Mountain, Manitoba
• "thin, relatively pure bioclastic limestone interbedded with calcareous shale or very argillaceous limestone. The shale or argillaceous limestone is largel reddish purple in outcrop. In the subsurface, it is medium olive gray or pinkish gray in eastern North Dakota, becoming darker olive gray in the central part of the state and almost black in the deepest wells in western North Dakota."

Size class: macrofossils

Preservation: original calcite

Reposited in the USNM

Primary reference: F.K. Lobdell. 1992. Arthrostylidae (Bryozoa: Cryptostomata) fromthe Gunn Member, Stony Mountain Formation (Upper Ordovician), North Dakota and Manitoba. North Dakota Geological Survey Miscellaneous Series 76:99-115 [S. Holland/S. Holland]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 64606: authorized by Steven Holland, entered by Steven Holland on 10.09.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Stenolaemata
 Cryptostomata - Arthrostylidae
Ulrichostylus costatus, Sceptropora facula, Sceptropora florida, Nematoporella ulrichi, Arthroclema pentagonalis, Arthroclema brevis
Sceptropora facula Ulrich 1888
Sceptropora florida Kiepura 1962
Nematoporella ulrichi Lobdell 1992
Arthroclema brevis Lobdell 1992