Upper Member, Shedhorn Formation of Montana (Permian of the United States)

Where: Montana (47.1° N, 109.4° W: paleocoordinates 18.4° N, 28.4° W)

• coordinate based on political unit

• basin-level geographic resolution

When: Upper Member (Shedhorn Formation), Wordian (266.9 - 264.3 Ma)

• member-level stratigraphic resolution

Environment/lithology: marine; sandstone

Primary reference: E. L. Yochelson and D. H. Van Sickle. 1968. Biostratigraphy of the Phosphoria, Park City, and Shedhorn Formations; Geology of Permian Rocks in the Western Phosphate Field. United States Geological Survey Professional Paper 313(D):572-660 [A. Miller/C. Ferguson/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 11276: authorized by Arnold Miller, entered by Chad Ferguson on 30.07.2001, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Bivalvia
 Nuculida - Nuculidae
Nuculopsis poposiensis Branson 1930 nut clam
 Trigoniida - Schizodidae
Schizodus sp. King 1844 clam
Schizodus cf. bifidus Ciriacks 1963 clam
 Trigoniida - Costatoriidae
"Costatoria sexradiata" = Procostatoria sexradiata
"Costatoria sexradiata" = Procostatoria sexradiata Branson 1930 clam
 Cardiida - Kalenteridae
Pseudopermophorus annettae Ciriacks 1963 clam
 Pectinida - Limipectinidae
Acanthopecten sp. Girty 1903 scallop
 Pectinida - Aviculopectinidae
Aviculopecten sp. M'Coy 1851 scallop
 Pectinida - Deltopectinidae
"Aviculopecten cf. alternatus" = Cyrtorostra varicostata
"Aviculopecten cf. alternatus" = Cyrtorostra varicostata Branson 1930 scallop
Gastropoda
 Bellerophontida -
Bellerophontoidea indet. M'Coy 1851 snail
 Bellerophontida - Bellerophontidae
Bellerophon deflectus Chronic 1952 snail
 Bellerophontida - Euphemitidae
"Euphemitopsis subpapillosus" = Euphemitopsis subpapillosa White 1876 snail
Euphemitopsis cf. paucinodosus Yochelson 1960 snail
Euphemites sp. Warthin 1930 snail
Warthia sp. Waagen 1880 snail
Scaphopoda
 Dentaliida - Dentaliidae
Plagioglypta sp. Pilsbry 1898 tusk shell
 Dentaliida - Prodentaliidae
"Plagioglypta canna" = Prodentalium canna
"Plagioglypta canna" = Prodentalium canna White 1874 tusk shell
Strophomenata
 Productida - Productellidae
aff. Echinauris sp. Muir-Wood and Cooper 1960
 Strophomenida - Chonetidae
Chonetes sp. Fischer de Waldheim 1830
 Orthotetida - Derbyiidae
Derbyia sp. Waagen 1884
Rhynchonellata
 Rhynchonellida - Wellerellidae
Wellerella sp. Dunbar and Condra 1932
 Athyridida - Athyrididae
Composita sp. Brown 1849
Lingulata
 Lingulida - Lingulidae
Lingula sp. BruguiƩre 1797
Stenolaemata
 Trepostomata -
Trepostomata indet. Ulrich 1882
entered as "Terpostomata"
Gnathostomata
  -
unclassified
  -
Porifera indet. Grant 1836