USGS Mesozoic loc. 22550 (Jurassic of the United States)

Where: Alaska (59.7° N, 153.3° W: paleocoordinates 31.6° N, 86.8° W)

• coordinate based on nearby landmark

When: Bowser Formation (Tuxedni Group), Callovian (166.1 - 163.5 Ma)

• 22550 - Probably Callovian, 515 to 545 m (1700-1800 ft) above base of Bowser Formation

Environment/lithology: marine; siltstone and massive sandstone

• From Detterman and Hartsock, 1966: "The heterogenous assemblage of rocks assigned to the Bowser Formation includes massive units of cliffforming graywacke-type sandstone and pebble-cobble conglomerate, thin-bedded, poorly consolidated shale, and massive siltstone. The character is further confused by rapid facies changes." "Present evidence shows that two faunal zones are

•present in the Bowser Formation. The lowest fauna occupies an interval 400-750 feet thick immediately overlying the Twist Creek Siltstone. The interval is mainly siltstone, but contains several massive sandstone and conglomerate units"

Size classes: macrofossils, mesofossils, microfossils

Collected by D. Hill in 1950; reposited in the USNM

Primary reference: T. P. Poulton. 1979. Jurassic Trigoniid Bivalves from Canada and Western United States of America. Geological Survey of Canada Bulletin 282 [G. Stanley/H. Shepherd/H. Shepherd]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 139589: authorized by George Stanley, entered by Hannah Shepherd on 14.02.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

 Trigoniida - Myophorelloidae
Vaugonia doroschini Eichwald 1871 clam