Middle Devonian, Alaska Range (USGS 2690) - Moffit (1954) (Devonian of the United States)

Also known as USGS 2690

Where: Valdez-Cordova County, Alaska (62.8° N, 132.3° W: paleocoordinates 7.2° S, 44.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Middle Devonian (393.3 - 382.7 Ma)

• The beds do not constitute a well defined group, but are assigned to middle Devonian on the basis of faunal composition and stratigraphically associated units. Devonian rocks in the Buck Creek area comprise a variety of clastic sedimentary rocks, including shale, quartzite, grit, and others, which are associated with limestone beds. All the beds are folded and tilted. No estimate of thickness is not known, but probably is several thousand feet.

• bed-level stratigraphic resolution

Environment/lithology: marine; coarse-grained, gray, blue limestone

• Beds are folded and locally are schistose, although not distinctly metamorphosed.
• Limestone is massive in structure, coarsely crystalline, and light bluish gray. Most of the group is made up of gray or black slate, hard gray siliceous beds, quartzite, yellowish sandy and gritty beds, chert conglomerate, and brown mica schist.

Size class: macrofossils

Preservation: cast, mold/impression

Reposited in the USGS

Collection methods: quarrying,

• Collections submitted to Edwin Kirk for identification.

Primary reference: F.H. Moffit. 1954. Geology of the eastern part of the Alaska Range and adjacent area. United States Geological Survey Professional Paper 989(D) [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 40660: authorized by Austin Hendy, entered by Austin Hendy on 26.06.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Representative of poorly preserved fauna
Anthozoa
 Favositida - Favositidae
Favosites sp. Lamarck 1816 tabulate coral
 Favositida - Alveolitidae
Alveolites sp. Lamarck 1801 tabulate coral
 Stauriida - Amplexidae
Amplexus sp. Sowerby 1814 horn coral