The Reading-Boyertown Hills of Pennsylvania are a part of the Appalachian Mountains, which lie between the Great Valley on the north and the Triassic belt on the south and extend from their western end in South Mountain, southwest of Wernersville, northeastward across eastern Pennsylvania into the Highlands of New Jersey and into New York (Figs. 1, 3, Pls. 52, 53).
These hills or irregular low linear ridges have an average altitude of 1,000 feet and reach a maximum altitude of 1,300 feet in South Mountain southwest of Wernersville. The ridges are separated by flat-bottomed, steep-sided valleys, and in their south-central part are divided by the wide flat Oley Valley (Pl. 52). The mountain belt is 10 miles wide north of Reading and narrows from this width north‐eastward.
The Paleozoic and Triassic rocks of the Reading, Boyertown, Quakertown, and Doylestown quadrangles were mapped from 1909 to 1914 by E. T. . . .