The area discussed in this paper is shown on the Delaware Water Gap sheet, in eastern Pennsylvania, and part of the Easton sheet adjoining the Water Gap sheet on the south (Fig. 1). The outstanding topographic feature here is Kittatinny Mountain, which extends from northeast to southwest across the northern section (Fig. 2). Parallel to, and southeast of, the mountain extends the “Great Valley” (some ten miles wide). The Delaware River cuts across mountain and valley, entering the narrow highlands near Easton. The mountain is a critical portion of the area, for it stands between two districts of Wisconsin glaciation.
Ordinarily the extent of any continental glacier is considered to be determined by the position of its terminal moraine. In this region, the statement is commonly made that the terminal edge crossed the Delaware just below Belvedere, extending from that place westward and then northwestward to . . .