Named (named in unpublished thesis). Type section is along Tascuela Canyon, mostly in E1/4 sec 13, T18S, R10E, but extending into sec 18, T18S, R11E, Pima Co, AZ in the Basin-and-Range province. A coarse basal conglomerate as much as 200 ft thick is overlain by 1,600-1,800 ft of maroon shale and argillite that contain sparse beds of sandstone, quartzite, and sandy limestone. Basal conglomerate consists of granules, pebbles, cobbles, and boulders of volcanic rocks from the underlying Ox Frame as well as quartzite, chert, and limestone of Paleozoic aspect. Disconformably overlies the Ox Frame Volcanics (new) and conformably overlain by Stevens Mountain Rhyolite (new). On basis of lithologic correlation with units in nearby ranges (Gardner Canyon Formation, Recreation Redbeds, Rodolfo Formation, lower part of Canelo Hills Redbeds) is assigned a Triassic age. Geologic map.

Source: GNU records (USGS DDS-6; Denver GNULEX).