Dinwoody Formation

Usage of Geologic Unit Name:
Dinwoody Formation (ID*,MT*,UT*,WY*)
Triassic, Early*
Geologic Province:
Montana folded belt province*
Yellowstone province*
Big Horn basin*
Green River basin*
Wind River basin*
Wasatch uplift*
Areal Extent:
Type Locality:
Not designated. Name probably taken from exposures at Dinwoody Canyon, western Fremont Co., in the Wind River Mountains, WY (Blackwelder, 1918).
(alphabetical): Freezout Shale Member (WY), Little Medicine Member (WY).
Unit Name History:
First used (Condit, 1916). Redescribed; Age modified; Areal limits (Blackwelder, 1918). Revised, Little Medicine Tongue named (Thomas, 1934). Revised (Newell and Kummel, 1942). Overview (Rubey, 1958; Cressman, 1964; Rioux and others, 1975).


Condit, D.D. and Stone, R.W., 1916, Relations of the Embar and Chugwater formations in Central Wyoming, IN Shorter contributions to general geology, 1916: U.S. Geological Survey Professional Paper, 98-O, p. O263-O270.

Blackwelder, E., 1918, New geological formations in western Wyoming: Washington Academy of Sciences Journal, v. 8, no. 13, p. 417-426.

Thomas, H.D., 1934, Phosphoria and Dinwoody tongues in lower Chugwater of central and southeastern Wyoming: American Association of Petroleum Geologists Bulletin, v. 18, no. 12, p. 1655-1697.

Newell, N.D. and Kummel, B., 1942, Lower Eo-Triassic stratigraphy, western Wyoming and southeast Idaho: Geological Society of America Bulletin, v. 53, no. 6, p. 937-996.

Rubey, W.W., 1958, Geology of the Bedford quadrangle, Wyoming: U.S. Geological Survey Geologic Quadrangle Map, GQ-109, 1 sheet, scale 1:62:500.

Cressman, E.R., 1964, Geology of the Georgetown Canyon-Snowdrift Mountain area, southeastern Idaho: U.S. Geological Survey Bulletin, 1153, 105 p.

Rioux, R.L., Hite, R.J., Dyni, J.R. and Gere, W.C., 1975, Geologic map of the Upper Valley quadrangle, Caribou County, Idaho: U.S. Geological Survey Geologic Quadrangle Map, GQ-1194, 6 p., 1 sheet, scale 1:24,000.

Rodland, David L; Kowalewski, Michal; Dettman, David L; Flessa, Karl W; Atudorei, Viorel; Sharp, Zachary D., 2003, High-resolution analysis of delta (super 18) O in the biogenic phosphate of modern and fossil lingulid brachiopods: Journal of Geology, v. 111, no. 4, p. 441-453.

Woods, Adam D., 2003, Widespread detrimental oceanic conditions along the western margin
of North America during the Early Triassic; anoxia without borders: Geological Society of America, Cordilleran Section, 99th annual meeting, Abstracts with Programs, v. 35, no. 4, p. 68.

Paull, Rachel K; Paull, Richard A., 1994, Shallow marine sedimentary facies in the earliest Triassic (Griesbachian) Cordilleran miogeocline, U.S.A.: Sedimentary Geology, v. 93, no. 3-4, p. 181-191.

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* show accepted USGS usage.
Note that data on this page contains information that has been partly revised from bibliographic resources available via the National Geologic Map Database GEOLEX:
The URL is: https://gotbooks.miracosta.edu/gonp/coloradoplateau/lexicon/dinwoody.htm
Last modified: 1/7/2011