McConnell-Trenholm Site (Miocene of the United States)

Also known as SDSM V2006-1

Where: Charles Mix County, South Dakota (43.5° N, 99.3° W: paleocoordinates 44.0° N, 96.0° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Fort Randall Formation, Barstovian (16.3 - 12.5 Ma)

Environment/lithology: terrestrial; lag, ferruginous, sandy conglomerate and massive, fine-grained, medium sandstone

• The stratigraphy consists of a basal, 5 m cross- bedded conglomerate lag overlain by 8-9 m of massive sandstone grading from medium grained at the base to fine grained near the top. Fossil material occurs exclusively in the informally named “iron-stained conglomerate”, a 15 to 45 centimeter (cm) cross-bedded conglomerate layer within the basal lag. This thin layer is distinguished from the surrounding lithology by a high concentration of oxidized iron sand giving it a distinct rust color, perhaps the result of periodic exposure.

Size class: macrofossils

• MT Site shows the most promise for intensive screenwashing work for continued recovery of microfossils.

Primary reference: D. C. Pagnac. 2012. Additions to the Vertebrate Faunal Assemblage of the Middle Miocene Fort Randall Formation in the Vicinity of South Bijou Hill, South Dakota, USA. The Mountain Geologist 49(1):19-34 [J. Marcot/J. Marcot]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 174577: authorized by Jonathan Marcot, entered by Jonathan Marcot on 15.11.2015

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Aves
 Accipitriformes - Accipitridae
Accipitridae indet.
Accipitridae indet. Viellot 1816 hawk
SDSM 78584
Mammalia
 Perissodactyla - Rhinocerotidae
Rhinocerotidae indet.
Rhinocerotidae indet. Gray 1821 rhinoceros
 Perissodactyla - Equidae
Equidae indet., Archaeohippus sp., Merychippus sp.
Equidae indet. Gray 1821 horse
Archaeohippus sp. Gidley 1906 anchitheriine horse
Merychippus sp. Leidy 1856 horse
 Artiodactyla - Antilocapridae
Antilocapridae indet.
Antilocapridae indet. Gray 1866 pronghorn
 Artiodactyla - Merycoidodontidae
Merycoidodontidae indet.
Merycoidodontidae indet. Cook 1912 oreodont
 Artiodactyla - Camelidae
Camelidae indet.
Camelidae indet. Gray 1821 camel
 Rodentia - Castoridae
"Monosaulax valentinensis" = Temperocastor valentinensis
"Monosaulax valentinensis" = Temperocastor valentinensis Stout 1999 beaver
 Proboscidea - Gomphotheriidae
Gomphotherium sp.
Gomphotherium sp. Burmeister 1837 gomphothere
Actinopteri
 Siluriformes - Ictaluridae
Ictaluridae indet.
Ictaluridae indet. Gill 1861 catfish
SDSM 76004
Gnathostomata
  -
Chondrichthyes indet.
Chondrichthyes indet. Huxley 1880 cartilaginous fish