The Geology of Texas - Vol. 1 - Stratigraphy by Sellards, Adkins and Plummer (1932)

"Millsap Lake Formation

The formation is largely shales with some conglomerates and thin sandstones. Limestones are present but are thin and usually lenticular in character. The members are, in descending order, Grindstone Creek beds, Brannon limestone, Steussy shales, Meek Bend limestone, Hill Creek beds, Dennis Bridge limestone, Kickapoo Falls limestone, Lazy Bend beds, and Dickerson beds (1398c). The part of the formation exposed measures 1600 feet. Fossils, including fusulinids, brachiopods, corals, bryozoa, bivalves, and gastropods, are locally abundant, being found chiefly in the lentils of limestone.

Type locality: Millsap Lake, Parker County; maximum thickness, 3000 feet or more."