1205-M-middle (Jurassic to of the United States)

Where: Bonneville, Madison, Teton County, Idaho (43.7° N, 111.3° W: paleocoordinates 38.6° N, 54.7° W)

When: C Member (Twin Creek Limestone Formation), Middle Jurassic to Middle Jurassic (174.1 - 145.0 Ma)

Environment/lithology: marine; lithified, fine-grained, gray, green, silty limestone

• Member C is a fine-grained gray to olive-gray silty limestone. Most of this rock is thin bedded, although some ledges of medium-bedded limestone are present in some areas. The limestone weathers into elongate pencil-shaped splinters, which are characteristic of the Twin Creek Limestone.

Size classes: macrofossils, mesofossils

Primary reference: M. H. Staatz and H. F. Albee. 1966. Geology of the Garns Mountain Quadrangle Bonneville, Madison, and Teton Counties, Idaho. United States Geological Survey Bulletin (1205) [A. Zaffos/E. Ito]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 184617: authorized by Andrew Zaffos, entered by Erika Ito on 14.03.2017

Creative Commons license: CC BY (attribution)

Taxonomic list

Bivalvia
 Ostreida - Gryphaeidae
Gryphaea planoconvexa Whitfield 1876 oyster
 Pholadida - Pleuromyidae
Pleuromya subcompressa Meek 1873 clam
Gastropoda
 Heterobranchia - Nerineidae
Nerinea sp. Deshayes 1827 snail