M1183 - Chichagof Bay Section (Oligocene of the United States)

Also known as M1183

Where: Aleutians East County, Alaska (55.7° N, 160.2° W: paleocoordinates 58.8° N, 154.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Stepovak Formation, Oligocene (33.9 - 23.0 Ma)

• Also within the type area of the Stepovak Formation ("series"). The Stepovak Formation reaches around 6500 ft in thickness and comprises sandstones and siltstones. Collection probably middle Oligocene. Collection from near middle of formation at top of unit 3.

• bed-level stratigraphic resolution

Environment/lithology: marine; brown, gray sandstone and black siltstone

• No paleoenvironmental reported.
• Tan to brown sandstone, massive, with some gray sandstone and black siltstone.

Size class: macrofossils

Collection methods: Collections examined by F.S. MacNeil and D. Taylor (USGS), 1962. Collections are reposited at USGS Menlo Park, or presumably USNM (not reported)

Primary reference: C.A. Burk. 1965. Geology of the Alaska Peninsula-island arc and continental margin (Part 1). Geological Society of America Memoir 99(1) [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 44109: authorized by Austin Hendy, entered by Austin Hendy on 01.09.2004, edited by Mihaela Krause

Creative Commons license: CC BY (attribution)

Taxonomic list

• No other fossils mentioned.
Gastropoda
 Neogastropoda - Fasciolariidae
? Perse sp. Clark 1918 snail
Bivalvia
 Pectinida - Pectinoidae
Vertipecten sp. n. sp. Grant and Gale 1931 scallop
Chlamys aff. ashiyaensis Nagao 1928 scallop
 Mytilida - Mytilidae
 Cardiida - Mactridae
? Spisula sp. n. sp. Gray 1837 clam
?= Mesodesma alaskaensis
 Nuculanida - Yoldiidae