Woods Ranch Member of Toroweap Formation

Usage of Geologic Unit Name:
Woods Ranch Member of Toroweap Formation (AZ*,NV*,UT*)
Permian, Early*
Geologic Province:
Plateau sedimentary province*
Basin and Range province*
Great Basin province*
Areal Extent:
Type Locality:
At north end of Hurricane Cliffs, 1.3 mi southeast of Woods Ranch house, SW/4 sec. 12, T. 33 N., R. 9 W., Mohave Co., AZ. Named for Woods Ranch in upper Whitmore Canyon, Mohave Co., AZ (Sorauf and Billingsley, 1991).
Unit Name History:
Assigned to Kaibab Group (Welsh and others, 1979). Named the upper member of the Toroweap Formation (Sorauf and Billingsley, 1991). Areal limits (Anderson and Hintze, 1993).
Description from Grand Canyon Area (from Billingsley, George H., 2000)

Woods Ranch Member—Gray and light-red, slope-forming gypsifereous siltstone and silty sandstone, interbedded with white laminated gypsum and gray thinbedded limestone. Gypsum beds are as much as 10 ft (3 m) thick. Unit as a whole weathers reddish gray. Bedding locally distorted due to solutioning of gypsum. Contact with underlying Brady Canyon Member is gradational and arbitrarily marked at top of cliff-forming limestone of the Brady Canyon. Variable thickness owing to solution of gypsum and channel erosion in upper part; averages about 65 ft (20 m) thick in southeastern quarter of map area, thickening to as much as 200 ft (60 m) in northwestern half 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.

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: http://pubs.usgs.gov/imap/i-2688/.).

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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:
The URL is: https://gotbooks.miracosta.edu/gonp/coloradoplateau/lexicon/toroweap_woodsranch.htm
Last modified: 1/7/2011