Mount Michelson (D50) (Miocene to of the United States)

Also known as USGS D50

Where: North Slope County, Alaska (70.0° N, 144.8° W: paleocoordinates 70.4° N, 143.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Nuwok Member (Sagavanirktok Formation), Late/Upper Miocene to Late/Upper Miocene (11.6 - 3.6 Ma)

• Fossils from interval 210 to 258 ft below top of measured section. Section estimated to be about 7000ft thick and containing silty shale, sandstone, and mudstone occurs in Carter Creek. Fossils only found in the upper 266 feet of the section. From Chlamys nuwokensis zone

• bed-level stratigraphic resolution

Environment/lithology: offshore; poorly lithified, concretionary, calcareous sandstone and concretionary, calcareous siltstone

• Interbedded sandstone and siltstone, with sparse calcareous concretions.

Size class: macrofossils

Reposited in the USNM

Collection methods: quarrying,

• Collections held at USNM, University of California, USGS (Washington) and USGS (Denver)

Primary reference: F.S. MacNeil. 1957. Cenozoic Megafossils of Northern Alaska. United States Geological Survey Professional Paper 294(C):99-126 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 37998: authorized by Austin Hendy, entered by Austin Hendy on 30.03.2004, edited by Mihaela Krause

Creative Commons license: CC BY (attribution)

Taxonomic list

• Representative of invertebrates
Annelida indet. Lamarck 1809
 Pectinida - Propeamussiidae
"Arctinula greenlandica" = Similipecten greenlandicus
"Arctinula greenlandica" = Similipecten greenlandicus Sowerby 1842 mud scallop
 Pectinida - Pectinoidae
Chlamys nuwokensis MacNeil 1957 scallop
? Chlamys nuwokensis MacNeil 1957 scallop
 Carditida - Astartidae
Astarte sp. Sowerby 1816 clam
 Cardiida - Ungulinidae
"? Taras sp." = Diplodonta
"? Taras sp." = Diplodonta Bronn 1831 clam
 Hiatellida - Hiatellidae
"Cyrtodaria camdenensis" = Cyrtodaria kurriana
"Cyrtodaria camdenensis" = Cyrtodaria kurriana Dunker 1861 clam
 Thraciida - Periplomatidae
 Thraciida - Thraciidae
"Thracia aff. truncata" = Thracia (Crassithracia) septentrionalis
"Thracia aff. truncata" = Thracia (Crassithracia) septentrionalis Jeffreys 1872 clam
= Thracia aff. myopsis
 Protobranchia - Nuculanidae
Nuculana morrisi pointed nut clam
 Cephalaspidea - Cylichnidae
 Naticoidea - Naticidae
 Terebratulida - Terebratulidae
"Terebratula" sp. Müller 1776
 Terebratulida - Cancellothyrididae
Terebratulina aff. retusa Linnaeus 1758
= Terebratulina aff. caput-serpentus