Pg. 29. Lake Bridgeport shales. Name here given to the shales and sandstones in Graford formation that occupy interval between Willow Point limestone below and Rock Hill limestone above. They increase in thickness from less than 100 feet, 2 miles northeast of Willow Point to 300+/- feet between Bridgeport and Chico, to 550 feet in Wise-Comanche No. 1 Spann well 2 miles east and 0.75 mile north of Chico, [Wise County, north-central Texas]. To west and north of Bridgeport they consist of (descending): (1) shale and flaggy sands, 45 feet; (2) prominent scarp-forming sandstone, brown, massive, and fine-grained; (3) very dark shales that weather yellow and brown and leave many claystone concretions. [Age is Pennsylvanian.]

Source: US geologic names lexicon (USGS Bull. 896, p. 1134).

Pamphlet [p. 14]. Lake Bridgeport shales [informal, unranked] in Jasper Creek Formation of Canyon Group. Shale and sandstone. Shale, gray, weathers to tan and yellowish-brown, locally dark-gray to black near base, silty, thin limestone lentils in northern outcrops, abundantly fossiliferous in at least four levels; sandstone mostly in upper part, light-brown, grayish-white, very fine-grained to fine-grained, locally calcareous, isolated flaggy thin and lenticular thick beds, laminated, ripple-marked. Lies below Rock Hill Limestone Member of Chico Ridge Limestone and above Willow Point Limestone Member of /Willow Point Formation; all of Canyon Group.
[On previous edition of map (1967), rocks mapped as Lake Bridgeport Shale Member of Graford Formation. Not separately mapped on 1991 edition of map. Rocks along the shore of Lake Bridgeport that were included in Lake Bridgeport Shale Member, are transferred to underlying /Willow Point Formation of Canyon Group. See also adjacent Wichita Falls-Lawton sheet, Texas Geol. Atlas, 1987.]

Source: Publication.