Lituya (M6525 (Miocene to of the United States)

Also known as USGS M6525; 75APr45A (Plafker field #)

Where: Lituya County, Alaska (58.4° N, 137.1° W: paleocoordinates 58.2° N, 133.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Topsy Formation, Burdigalian to Burdigalian (20.4 - 11.6 Ma)

• Topsy Formation consists of about 365 metres of hard calcareous siltstone and sandstone that intertongue with and in part, conformably overlie the Cenotaph Volcanics. Topsy Formation underlies Yakataga Formation (early Miocene-Holocene). Age originally assigned to post-early Oligocene to pre-middle Miocene based on volcanics (Plafker, 1967). Biostratigraphy in this reference constrains age to early or middle Miocene

• bed-level stratigraphic resolution

Environment/lithology: coastal; lithified siltstone and lithified sandstone

• Because discontinuous outcrops and structurally complex geology in this area preclude reliable lithiologic correlations with other formations in this region and because no well-preserved, age-diagnostic fossils have been reported before from these strata, the age and depositional environment of the Topsy Formation have been the subjects for speculation.
• Topsy Formation "consists of marine siltstone and sandstone"; "hard calcareous siltstone and sandstone"

Size class: macrofossils

Reposited in the USNM

Collection methods: quarrying,

• Fossil collections are housed in the USGS, Menlo Park, and type specimens in the NMNH, Washington

Primary reference: L. Marincovich. 1979. Miocene molluscks of the Topsy Formation, Lituya district, Gulf of Alaska Tertiary Province, Alaska. United States Geological Survey Professional Paper 1125(C):C1-C14 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 37385: authorized by Austin Hendy, entered by Austin Hendy on 14.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Representative of molluscan elements; no mention of other invertebrate groups
 Cardiida - Tellinidae
Macoma albaria Conrad 1849 tellin clam
 Lucinida - Thyasiridae
"Thyasira cf. disjuncta" = Conchocele conradii
"Thyasira cf. disjuncta" = Conchocele conradii Rosenkrantz 1942 clam
 Nuculida - Nuculidae
Acila (Truncacila) sp. Grant and Gale 1931 divaricate nutclam
 Neogastropoda - Buccinidae
? Colus sp. Röding 1798 true whelk
  - Neptuneidae