Pg. 430, 433. Sanatoga member of Brunswick formation. The highest black-shale member of Brunswick formation studied by writer. (Term black shale as here used covers all gray, green, or black shales in Brunswick and Lockatong formations.) Consists of 200+/- feet of dark-gray and green shale. Along Perkiomen Creek lies 2,000+/- feet above Graters members of Brunswick, but in Schuylkill section it is probably only 1,100 feet above the Graters. Forms part of Perkasie shales of Lyman. Wherry has pointed out (Phila. Acad. Nat. Sci. Proc., v. 64, p. 376, 1912) that the Perkasie should not be regarded as a definite formation, since a large part of it is merely red shale which has been altered by the diabase intrusion. The Sanatoga member, however, although slightly altered in places, does not owe its dark color nor most of its hardness to baking. Age is Late Triassic (Newark).
Named from excellent exposures in a large quarry and in the railroad cut at Sanatoga Station on Schuylkill River, Montgomery Co., southeastern PA.

Source: US geologic names lexicon (USGS Bull. 896, p. 1903).

Pg. 179. Sanatoga shale, 200 feet of dark shale in Brunswick formation. Exposed at Sanatoga, Schwenksville, and Ledarachsville [all in Montgomery County, southeastern Pennsylvania. Age is Late Triassic (Newark).

Source: US geologic names lexicon (USGS Bull. 896, p. 1903).