104 Quaternary Formations of Southern New Jersey. 



sandy. In the latter, most of the gravel is near the top. In the. 

 former, gravel predominates over sand, and considerable beds 

 of arkose sand free from gravel are rare. 



For the eastern patches, the material near Ellisburg is char- 

 acteristic. Here, at the top (at the 100 foot level) is 4 feet of 

 gravel, with sand and loam matrix. The whole is very compact, 

 and its stratification irregular. Beneath the gravel there is at 

 least 18 feet of arkose sand, yellow to white in color, compact 

 and well, stratified, with an occasional seam of pebbles. Hills 

 at slightly higher levels (102 feet, 108 feet) have caps of gravel, 

 apparently the upper member of the formation, resting on Cre- 

 taceous. These hills appear to represent about the upper level 

 of Pensauken deposition here. 



In the large area north and northwest of Moorestown and 

 Hartford, the upper part of the formation has more gravel, and 

 the lower part more sand ; but at the very base, gravel is likely 

 to occur. There are many pits where the sand and gravel are 

 worked for road material. One pit shows : 



3) 2 feet loam and sand with quartz pebbles. 

 2) 8 feet coarse sand, more or less cemented by iron oxide. 

 1) 6 feet sand and fine gravel, well stratified, with occasional bowl- 

 ders 1 foot in diameter, and with bits of red shale. 



In the more westerly areas, the difference in constitution is 

 brought out by a few sections. Thus west of Merchantville, a 

 section showed 7 feet of compact gravel and arkose sand of a 

 brownish color, above 4 feet of similar material of lighter color. 



At Fish House and Delair extensive excavations have shown 

 a heavy bed of black clay (Fig. 49), overlain in places by typical 

 Pensauken gravel, and underlain by gravel of Pensauken type, 

 quite like that at low levels in Philadelphia (p. 106). The clay 

 contains unio shells, one species of which still lives in the river 

 in the vicinity. 



South of Morris Station, on Pensauken Creek, the place which 

 gave name to the formation, exposures of the formation over 

 the Cretaceous clay are numerous. The following is a typical 

 section : 



