Pensauken Formation — Locae Details. 125 



4) 3 feet of gravelly loam. 



3) 1 foot of coarse stratified sand. 



2) Y2 foot of gravel. 



1) 5 feet of coarse arkose sand, horizontally stratified. 



Between Locust Corner and Hightstown exposures are rare. 

 Some cobbles mark the surface, and one angular sandstone 

 bowlder 6 feet long was seen. 



In Hightstown the base of the Pensauken has an altitude of 

 between 90 and 100 feet. Northwest of Locust Corner, and again 

 a mile down stream, Pensauken occurs repeatedly at levels below 

 90 feet. A mile north of the Co,rner, the base is below 80 feet, 

 and where the wagon road east from Princeton Junction crosses 

 the Millstone, the base is apparently below 70 feet. These eleva- 

 tions show that the pre-Pensauken base declines gradually from 

 the southeast to the northwest, the most abrupt change being 

 at the southeast, where the formation comes against the old 

 headlands: 



The character of the Pensauken at Hightstown is essentially 

 the same as at Allentown and Robbinsville, — light-colored arkose 

 sand, with some pebbles scattered through it. It is, or has been, 

 well exposed in the railway cuts in the vicinity. T0 1 the eastward, 

 arkose sand occurs even to Etra, a mile and a half southeast of 

 Hightstown, where this phase of the formation grades into the 

 non-arkose phases farther east. In general, the arkose phase is 

 limited at the southeast by the interrupted scarp referred to, a 

 scarp which consisted of headlands separated by valleys 30 to 50 

 feet deep, and 1 to 3 miles wide. 



The vicinity of Hightstown, contrasted with the region farther 

 southwest, as at Allentown, shows one important difference. In 

 the latter place, the Pensauken is arkose in its basal parts only, 

 while near Hightstown it is arkose up to altitudes of 130 feet, 

 or even to 150 feet. The 151-foot hill a mile and a half south 

 of Hightstown, covered with arkose sand, suggests that the 

 Pensauken was built up to this level in this vicinity. 



Two miles south of Hightstown, Cretaceous sand appears at 

 the surface at the top of the 153-foot hill and on the slopes below, 

 while a mile to the northwest, the 151-foot hill seems to be 



