Milligan Creek, locality no. 50a (Devonian of the United States)

Also known as USGS D29(SD)

Where: Jefferson County, Montana (45.9° N, 111.6° W: paleocoordinates 14.2° S, 46.4° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Three Forks Shale Formation, Famennian (372.2 - 358.9 Ma)

• 110-200 feet below Lodgepole Limestone, 20-90 feet below base of upper siltstone unit.

• group of beds-level stratigraphic resolution

Environment/lithology: offshore; lithified, ferruginous, brown, red siltstone and green shale

• reddish-brown siltstone interbedded with olive shale.

Reposited in the USGS

Primary reference: G. D. Robinson. 1963. Geology of the Three Forks Quadrangle, Montana. United States Geological Survey Professional Paper 370:1-143 [J. Alroy/M. Sommers/J. Ju]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 7239: authorized by John Alroy, entered by Mike Sommers on 19.05.2000

Creative Commons license: CC BY (attribution)

Taxonomic list

• only brachiopods and cephalopods listed
Rhynchonellata
 Spiriferida - Spiriferidae
 Spiriferida - Ambocoeliidae
? Crurithyris sp. George 1931
 Spiriferida - Cyrtospiriferidae
 Athyridida - Athyrididae
Cephalopoda
 Goniatitida - Kirsoceratidae
"Tornoceras crebriseptum" = Pernoceras crebriseptum
"Tornoceras crebriseptum" = Pernoceras crebriseptum Raymond 1909 ammonite
 Goniatitida - Prolobitidae
Raymondiceras simplex Raymond 1909 ammonite
 Clymeniida - Platyclymeniidae
"Platyclymenia (Pleuroclymenia) americana" = Pleuroclymenia americana, "Platyclymenia (Pleuroclymenia) polypleura" = Pleuroclymenia americana
"Platyclymenia (Pleuroclymenia) americana" = Pleuroclymenia americana Raymond 1907 ammonite
sgn. (Pleuroclymenia)
"Platyclymenia (Pleuroclymenia) polypleura" = Pleuroclymenia americana Raymond 1907 ammonite
sgn. (Pleuroclymenia)
 Orthocerida - Orthoceratidae