West Slope of Derry Hills, Arrey Formation, Collection 6 (Carboniferous of the United States)

Where: Sierra County, New Mexico (32.8° N, 107.3° W: paleocoordinates 7.5° S, 46.1° W)

• small collection-level geographic resolution

When: Arrey Formation (Green Canyon Group), Carboniferous (358.9 - 298.9 Ma)

• Derry series is divided into 2 groups and 4 formations. At the type locality, the Derryan consists of alternating limestone (80 %) and shales (20%), approximately 127 feet thick, lying unconformably upon Devonian shale. Unit 6a = 1.0 ft. Unit 6b = 1.0 ft. Unit 6c = 1.5 ft. Unit 6d = 0.3 ft. Unit 6e = 0.3 ft. Unit 6f = 0.2 ft. Unit 6g = 0.5 ft. Unit 6h = 0.2 ft. Unit 6i = 0.5 ft.

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified, shelly/skeletal, gray limestone and shale

• Unit 6a: Limestone, gray, coarse-grained, crinoidal. Unit 6b: Shale, calcareous; weathers tan; very fossiliferous. Unit 6c: Limestone, gray, hard, crinoidal; calcite film on surface. Unit 6d: Shale, calcareous; weathers tan. Unit 6e: Limestone, dark-gray, crinoidal. Unit 6f: Shale, calcareous; weathers tan. Unit 6g: Limestone, dark-gray, crinoidal; weathers tan. Unit 6h: Shale, highly calcareous; weathers light tan. Unit 6i: Limestone, dark-gray, crinoidal; green coloring on fresh surfaces.

Size classes: macrofossils, microfossils

Primary reference: J. L. Gehrig. 1958. Middle Pennsylvanian Brachiopods From the Mud Springs Mountains and Derry Hills, New Mexico. State Bureau of Mines and Mineral Resources, Memoir 3 1-24 [T. Olszewski/K. Nell]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 9869: authorized by Tom Olszewski, entered by Katrina Nell on 20.02.2001

Creative Commons license: CC BY (attribution)

Taxonomic list

• Except in noting the presence of crinoids, only brachiopods and fusulinids reported.
Strophomenata
 Productida -
Marginifera sp. Waagen 1884
 Productida - Productidae
Rhynchonellata
 Spiriferinida - Punctospiriferidae
"Punctospirifer kentuckyensis" = Punctospirifer kentuckensis
"Punctospirifer kentuckyensis" = Punctospirifer kentuckensis Shumard 1855
 Athyridida - Neoretziidae
Hustedia mormoni Marcou 1858
 Athyridida - Athyrididae
Composita sp. Brown 1849
 Spiriferida - Trigonotretidae
Neospirifer sp. Fredericks 1919
 Orthida - Rhipidomellidae
Rhipidomella carbonaria Shumard and Swallow 1858
Foraminifera
 Fusulinoidea - Eostaffellidae
 Fusulinoidea - Profusulinellidae