126 CLAYS AND CLAY INDUSTRY. 



feet below sea level. Even as far north as Closter the surface 

 of the rock is at least 20 feet below the sea level, according- to the 

 records of wells. 



"The records of borings in the vicinity of Newark are in 

 keeping with the above figures. 



"This clay was deposited in standing water. Such a body of 

 water, therefore, covered the lower lands west of the Palisade 

 ridge, probably as far north as Neuvy, after the departure of 

 the ice. The surface of the clay at the north is about 30 feet 

 above sea level. The surface of the water in which the clay was 

 deposited was, therefore, at least this much above present sea 

 level in the latitude of Neuvy. Not only this, but the water in 

 which the clay was deposited was probably not extremely shallow. 

 While no considerable depth need be assumed for it, it is safe 

 to conclude that the surface of the clay is somewhat below the 

 surface of the water in which it was deposited. Furthermore, 

 the clay was deposited after the ice was sufficiently far north 

 of the site of deposition, so that coarse materials were not readily 

 available. It is not certain that the clay at Hackensack and below 

 was strictly contemporaneous with that at Neuvy. The deposi- 

 tion of clay to the south may well have begun earlier than its 

 deposition to the north. 



"It is commonly believed that the ice sheet depressed the sur- 

 face on which it rested, and that, as it melted, the unburdened 

 earth crust reacted by rising. Before the deposition of the clay 

 in the northern part of the Hackensack basin, the land may have 

 risen, so as to make the water shallower than at an earlier time. 

 At any rate, there is good evidence of post-Glacial submergence 

 to the extent of fully 30 feet near the northeastern corner of 

 the State. Considering the depth of water necessary for the 

 deposition of the clay, and the rise which may have taken place 

 as the ice melted back, it is not unreasonable to suppose that the 

 region about Westwood was submerged to the extent of 60 to 

 80 feet, the height of what appear to be delta fronts, at the time 

 the ice was retreating; for these deltas, if such they are, were 

 probably made while the edge of the ice was in the immediate 

 vicinity, and somewhat before the deposition of the clay. 



