False Pass (A-169) (Miocene of the United States)

Also known as University of Alaska A-169; USGS M5044

Where: Aleutians East County, Alaska (54.9° N, 163.4° W: paleocoordinates 55.9° N, 161.8° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Tachilni Formation, Tortonian (11.6 - 7.2 Ma)

• Formation crops out continuously from the coast west of Cape Tachilni from Morzhovoi Bay to False Pass and possibly of Deer Island. Thickness of the Tachilni Fm is not known because its base is not exposed, but is estimated to be as much as 460 m thick, although not more than 250 m and any outcrop. Disconformably overlies volcaniclastic Belkofski Fm, and is unconformably overlain by Pliocene-Holocene volacanic flows and breccia.

• bed-level stratigraphic resolution

Environment/lithology: coastal; fine-grained, medium, brown, gray sandstone

• Composed mostly of dark brown to light greenish-gray, fine- to coarse-grained sandstone, abundant similarly colored siltstone, with some pebble conglomerate and black shale....mainly a fine- to medium-grained sandstone.

Size class: macrofossils

Reposited in the CAS, USNM

Collection methods: quarrying,

• Also collections at University of Alaska (UA), Fairbanks, Alaska

Primary reference: L. Marincovich. 1983. Molluscan paleontology, paleoecology, and North Pacific correlations of the Miocene Tachilni Formation, Alaska Peninsula, Alaska. Bulletin of American Paleontology 84(317):1-155 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 37414: authorized by Austin Hendy, entered by Austin Hendy on 14.03.2004, edited by Mark Uhen

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for molluscan taxa
Gastropoda
 Neogastropoda - Buccinidae
 Sorbeoconcha - Naticidae
Polinices (Euspira) pallidus, "Natica (Cryptonatica) clausa" = Cryptonatica affinis
Polinices (Euspira) pallidus Broderip 1829 moon snail
"Natica (Cryptonatica) clausa" = Cryptonatica affinis Gmelin 1791 moon snail
Bivalvia
 Mytilida - Mytilidae
Crenomytilus coalingensis Arnold 1909 mussel
 Cardiida - Veneridae
"Protothaca (Protothaca) staleyi" = Leukoma staleyi
"Protothaca (Protothaca) staleyi" = Leukoma staleyi Gabb 1866 venus clam
 Cardiida - Ungulinidae
"Felaniella parilis" = Diplodonta parilis
"Felaniella parilis" = Diplodonta parilis Conrad 1848 clam
 Cardiida - Mactridae
"Spisula (Mactromeris) albaria" = Mactromeris albaria, "Spisula (Mactromeris) polynyma" = Mactromeris polynyma
"Spisula (Mactromeris) albaria" = Mactromeris albaria Conrad 1848 clam
"Spisula (Mactromeris) polynyma" = Mactromeris polynyma Stimpson 1860 clam
 Cardiida - Cardiidae
"Clinocardium meekianum" = Clinocardium (Clinocardium) meekianum Gabb 1866 cockle
 Cardiida - Tellinidae
"Peronidia aff. lutea" = Tellina (Megangulus) lutea Gray 1828 tellin clam
Subspecies: Peronidia aff. P. lutea alternidentata
 Hiatellida - Hiatellidae
 Carditida - Carditidae
Cyclocardia sp. Conrad 1867 clam
 Nuculida - Nuculidae
"Acila (Truncacila) empirensis" = Acila (Truncacila) castrensis
"Acila (Truncacila) empirensis" = Acila (Truncacila) castrensis Hinds 1843 divaricate nutclam
Echinoidea
 Clypeasteroida - Echinarachniidae
Echinarachnius cf. ungaensis Wagner 1974 sand dollar
Remondella waldroni n. sp. Wagner 1974 sand dollar