False Pass (A-170) (Miocene of the United States)

Also known as University of Alaska A-170

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 37415: authorized by Austin Hendy, entered by Austin Hendy on 14.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for molluscan taxa
Bivalvia
 Arcida - Glycymerididae
"Glycymeris grewingki" = Glycymeris (Axinola) septentrionalis
"Glycymeris grewingki" = Glycymeris (Axinola) septentrionalis Middendorf 1849 clam
 Pectinida - Pectinoidae
"Chlamys (Swiftopecten) cosibensis" = Chlamys (Chlamys) cosibensis
"Chlamys (Swiftopecten) cosibensis" = Chlamys (Chlamys) cosibensis Yokoyama 1911 scallop
Subspecies: Chlamys (Swiftopecten) cosibensis cosibensis
 Carditida - Carditidae
 Pholadida - Myidae
Mya (Arenomya) elegans softshell clam
Mya (Mya) truncata Linnaeus 1758 softshell clam
 Cardiida - Chamidae
Chama sp. Linnaeus 1758 jewel box
 Cardiida - Mactridae
"Spisula (Mactromeris) albaria" = Mactromeris albaria, "Spisula (Mactromeris) brevirostrata" = Mactromeris brevirostrata
"Spisula (Mactromeris) albaria" = Mactromeris albaria Conrad 1848 clam
"Spisula (Mactromeris) brevirostrata" = Mactromeris brevirostrata Packard 1916 clam
 Cardiida - Ungulinidae
"Felaniella parilis" = Diplodonta parilis
"Felaniella parilis" = Diplodonta parilis Conrad 1848 clam
 Cardiida - Tellinidae
"Peronidia aff. lutea" = Tellina (Megangulus) lutea Gray 1828 tellin clam
Subspecies: Peronidia aff. P. lutea alternidentata
Macoma (Macoma) cf. astori Dall 1909 tellin clam
 Cardiida - Cardiidae
"Clinocardium meekianum" = Clinocardium (Clinocardium) meekianum Gabb 1866 cockle
 Thraciida - Periplomatidae
Gastropoda
 Neogastropoda - Buccinidae
 Naticoidea - Naticidae
"Natica (Cryptonatica) clausa" = Cryptonatica affinis
"Natica (Cryptonatica) clausa" = Cryptonatica affinis Gmelin 1791 moon snail
 Calyptraeoidea - Calyptraeidae
Calyptraea sp. Lamarck 1799 slipper shell
  - Neptuneidae
 Trochoidea - Trochidae
Margarites (Pupillaria) sp. Dall 1909 top snail