Dillingham - #1 (McRoberts & Blodgett, 2000) (Triassic of the United States)

Also known as Locality #1

Where: Dillingham County, Alaska (60.9° N, 157.4° W: paleocoordinates 7.8° N, 80.4° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Holitna Group, Norian (228.0 - 208.5 Ma)

• No formal stratigraphic name has been applied to the Triassic rocks of the Taylor Mountain D-2 and D-3 quadrangles. The term "Holitna Group" has been suggested to be too broadly defined (includes all Paleozoic carvonates in the Holitna River section). LePain and others (2000) designated these strata as Tzrlc (silty limestone and chert) on their geological map. Total thickness of Triassic rocks in section is unknown, although a minimum thickness of 300 m is estimated.

• bed-level stratigraphic resolution

Environment/lithology: marine; yellow, silty, calcareous mudstone

• From Farewell terrane of southwestern and west-central Alaska. Farewell terrane is of early and middle Paleozoic age and probably originated as a rifted continental margin sequence derived from the Siberian continent by a Devopnian or slightly later rifting event. Deepening upward succession
• Composed of yellow-orange-weathering platy, silty lime mudstone beds.

Size class: macrofossils

Preservation: recrystallized, replaced with silica

Collection methods: quarrying,

• Collected by R.B. Blodgett (1984, 1999). Field #84RB32, 99RB35. Fossil fauna composed of numerous mollusks (bivalves, gastropods) and lesser brachiopods. Collections deposited in U of Alaska Museum in Fairbanks

Primary reference: C. A. McRoberts and R. B. Blodgett. 2000. Late Triassic (Norian) mollusks from the Taylor Mountains quadrangle, southwestern Alaska. United States Geological Survey Professional Paper 1662:55-67 [A. Miller/A. Hendy/S. Kolbe]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 39896: authorized by Austin Hendy, entered by Austin Hendy on 11.06.2004, edited by Uta Merkel

Creative Commons license: CC BY (attribution)

Taxonomic list

• Comprehensive for mollusca
Bivalvia
 Ostreida - Gryphaeidae
Gryphaea arcuataeformis Kiparisova 1936 oyster
 Ostreida - Cassianellidae
Cassianella cordillerana n. sp. McRoberts and Blodgett 2000 oyster
 Carditida - Astartidae
Astarte sp. Sowerby 1816 clam
 Carditida - Carditidae
Tutcheria densestriata Koerner 1937 clam
 Cardiida - Cardiidae
 Trigoniida - Trigoniidae
Minetrigonia cf. suttonensis Clapp and Shimer 1911 clam
Gastropoda
 Prosobranchia - Protorculidae
Chulitnacula alaskana Smith 1927 snail
 Neritoidea - Neritariidae
Neritaria nuetzeli n. sp. McRoberts and Blodgett 2000 snail
 Murchisoniina - Zygopleuridae
Andangularia wilsoni n. sp. McRoberts and Blodgett 2000 snail