Brady Canyon Member of Toroweap Formation

Usage of Geologic Unit Name:
Brady Canyon Member of Toroweap Formation (AZ*,NV*,UT*)
Permian, Early*
Geologic Province:
Great Basin province*
Plateau sedimentary province*
Basin and Range province*
Areal Extent:
Type Locality:
In Brady Canyon about 12.8 mi north of Colorado River on east side Toroweap Valley, Mohave Co., AZ (Sorauf and Billingsley, 1991).
Unit Name History:
Revised, assigned to Kaibab Group (Welsh and others, 1979). Overview (Rigby, 1988). Named the middle member of Toroweap Formation; Reference section (Sorauf and Billingsley, 1991). Areal limits (Anderson and Hintze, 1993).
Description from Grand Canyon Area (from Billingsley, George H., 2000)

Brady Canyon Member—Gray, cliff-forming, thin- to medium-bedded [1–5 ft (0.05– 1.4 m)], fine- to coarse-grained, fetid, fossiliferous limestone. Weathers dark gray. Includes thin-bedded dolomite in upper and lower parts. Contains white and gray chert nodules that make up less than 8 percent of unit. Contact with underlying Seligman Member is gradational and arbitrarily placed at base of cliffforming limestone of the Brady Canyon. Thickness about 40 ft (12 m) at eastern edge of map area, increasing to about 130 ft (40 m) at western edge of map area.


Welsh, J.E., Stokes, W.L. and Wardlaw, B.R., 1979, Regional stratigraphic relationships of the Permian "Kaibab" or Black Box Dolomite of the Emery high, central Utah, IN Baars, D.L., ed., Permianland: Four Corners Geological Society Field Conference Guidebook, 9th Field Conference, Moab, UT, September 27-30, 1979, p. 143-149.

Rigby, J.K., 1988, The first reported occurrence of the Demosponge Haplistion in the Permian Toroweap Formation: Brigham Young University Geology Studies, v. 35, p. 9-13.

Sorauf, J.E. and Billingsley, G.H., 1991, Members of the Toroweap and Kaibab Formations, Lower Permian, northern Arizona and southwestern Utah: The Mountain Geologist, v. 28, no. 1, p. 9-24.

Anderson, R.E. and Hintze, L.F., 1993, Geologic map of the Dodge Spring quadrangle, Washington County, Utah and Lincoln County, Nevada: U.S. Geological Survey Geologic Quadrangle Map, GQ-1721, 1 sheet, scale 1:24,000.

Billingsley, George H., 2000, Geologic Map of the Grand Canyon 30' by 60' Quadrangle, Coconino and Mohave Counties, Northwestern Arizona: U.S. Geological Survey Geologic Investigation Series I-2688, Available on-line at:

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Note that data on this page contains information that has been partly revised from bibliographic resources available via the National Geologic Map Database GEOLEX:
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Last modified: 1/7/2011