PLEISTOCENE CLAYS. 133 



PENSAUKEN. 



The Pensauken formation has been somewhat fully discussed 

 in the previous reports of the Survey. 1 It is predominantly a 

 sand and gravel formation occurring chiefly in two belts. "One 

 •of these runs across the State in a northeast-southwest direction 

 from the head of Raritan bay nearly to Salem; the other runs 

 along the east side of the State from the vicinity of Asbury Park 

 to Bridgeton. The former belt is narrow and clearly defined, and 

 within it the formation occurs in a series of closely associated 

 patches, some of which are large and some small ; the latter belt 

 is wider and less well defined, the patches of the formation being 

 more widely separated." 2 The Pensauken formation is believed 

 to be contemporaneous in age with an earlier ice epoch than that 

 to which the Belvidere-Perth Amboy moraine is referred. The 

 extent to which the formation has been removed by erosion, and 

 the deeply dissected condition of the remnants, indicate a much 

 greater age than the Cape May formation or the great mass of 

 glacial drift. 



The Fish-House clays. — Although this formation is predom- 

 inantly sand and gravel, yet at Fish House (137), a few miles 

 north of Camden, there are thick beds of black clay which are 

 apparently intercalated in the sands of this formation. Since 

 these clays are somewhat fossiliferous, they have long attracted 

 the attention of geologists, and many diverse views have been 

 held as to their age. A few years ago a series of borings was 

 made to determine their extent, and the data thus obtained made 

 it possible to fix their stratigraphic position, The sections were 

 carefully examined at the time by Lewis Woolman, and the fol- 

 lowing facts both as to stratigraphy and fossils are mainly sum- 

 marized from his report. 3 



In the excavations the clay attains a thickness of 27 or 28 

 feet. The upper 2 or 3 feet is yellowish in color, as is also the 



1 Notably the Ann. Rep. for 1896, 1897. 



2 Ann. Rep. 1897, P- 15- 



'Ann. Rep. of the State Geologist of N. J., 1896, pp. 201-244. 



