n8 Quaternary Formations of Southern New Jersey. 



Cape May formation at an elevation of about 60 feet. The 

 Pensauken is traceable westward by means of excavations, and 

 in ravines, to within three-fourths of a mile of the Delaware, 

 where its upper surface, beneath the Cape May (Trenton gravel) 

 formation, has an altitude of 20 to 30 feet. Pits south and 

 west of White Horse show the material to be very compact, but 

 not very coarse gravel, of a reddish-yellow color. Large cobbles 

 and even bowlders occur on the surface, doubtless left there by 

 the removal of part of the formation. The surface here is 

 characterized by many undrained hollows, comparable to those 

 in the surface of glacial drift, where its topography is relatively 

 plane. 



The Mercerville-Robbinsville-Allentown area. — The surface of 

 this area has an altitude ranging from about 100 feet at the 

 west, to about 140 feet (maximum 153 feet) at the east. At 

 the west the base of the Pensauken has an altitude of about 80 

 to 90 feet, but is as low as 70 feet, or possibly 60 feet, at some 

 points near pre-Pensauken valleys. 



The base rises to 90-^5 feet at Robbinsville, and 120--130 

 feet at points on the eastern border of the area, near New Sharon. 

 Where the Pensauken occurs at the lower levels on slopes, it is 

 possible that it has been displaced down slope since Pensauken 

 time. The base appears to remain relatively low (90 to 95 feet 

 or less) to a point 2y 2 miles east of Robbinsville, where it rises 

 rather promptly to 130 feet along the site of what was probably 

 an old headland extending northwest from Egg Tavern. 



In this general area the Pensauken is arkose, and contains bits 

 of crystalline rock, shale, etc., as normally. It has a depth of 30 

 or 40 feet, maximum, but its average is much less. 



A good exposure on the railway near Robbinsville showed : 



3) 2 feet of quartzose sand and loam. 



2) 6 feet of horizontally stratified gravel and sand, with pockets of 



3) sunk into its surface. 

 1)7 feet of coarse arkose sand, somewhat cross-bedded, with bottom 



not seen. 



Two miles southwest of Robbinsville, in the north bank of 

 Back Creek, at 60 feet, the material is much coarser, cobbles, and 



