Is Pleistocene formation mapped in southwestern part of map sheet in upper reaches of Double Mountain Fork Brazos River in southeastern Lynn and southwestern Garza Cos, TX (northeastern Permian basin). Map unit described as sand, silt, and clay, gravel at base. Sand, fine- to medium-grained quartz, silty in part, some caliche nodules, thin-bedded to massive, white, gray, brownish gray, grayish red. Silt and clay, locally bentonitic, indistinctly bedded, light gray, olive gray, greenish gray; weathers white, light gray, pink. Molluscan and vertebrate fossils. Thickness 85 ft, feathers out laterally. (Kansan)

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

Pg. 240+ (fig. 7.1). Tule Formation. Recognized in Texas. Includes (descending): Lava Creek B ash (Pearlette type O), about 0.67 Ma; Mayfield Ranch fauna; Rock Creek fauna; Martin Ranch fauna; and Cerro Toledo X ash, about 1.2 to 1.3 Ma (by tentative correlation). Age is Irvingtonian NALMA; Matuyama to Brunhes chron zone (reversed polarity zone 1r.2r to normal polarity zone 1n).

Source: Publication.