128 CLAYS AND CLAY INDUSTRY. 



at Riveredge, a little south of the depot, in a temporary excava- 

 tion. Here the section was as follows : 



"(3) Sand, 4 feet. 



"(2) Clay and sand, interlam mated, 6 feet. 



"(1) Clay, black from the presence of organic matter. 



"The old soil in this case was about 10 feet above sea level. 



"These sections show that after the clay was deposited, the 

 surface was exposed for a time, and that vegetation grew upon 

 it, after which it was depressed sufficiently to< allow of the deposi- 

 tion of the overlying sand." 1 



Clay of the lower Passaic valley.— Clay, very similar in ap- 

 pearance to that at Hackensack, was formerly dug in the valley 

 of a little creek on the west side of the Passaic, one-half mile 

 or more below Passaic Bridge. It lies beneath several feet of 

 coarse gravel, which increases in thickness towards the hill. The 

 clay is reported to be 13 feet in thickness, the upper 6 or 8 feet 

 being yellow, the lower part blue. Owing to the heavy overbur- 

 den it is not readily available. 



Clays of the upper Passaic basin.- — Clay occurs over wide 

 areas in the basin of the upper Passaic and its tributaries in the 

 area formerly occupied by the glacial Lake Passaic. 2 It underlies 

 all the area of Great swamp and the surrounding low ground, 

 where it does not occur above an altitude of 240 feet. The clay 

 of the eastern half O'f this area, as far west as the road from New 

 Vernon to Gillette, is covered with fine sandy loam, which east 

 of the longitude of Green Village changes into sand and gravel. 

 Clay more or less buried by sand and gravel has also' been found 

 1) south of Morristovni, 2) on the banks of the brook southwest 

 of Convent and 3) at the bottom of deep wells southwest of 

 Madison. 



•The clav in the Great swamp area attains a considerable thick- 

 ness. Wells 25 or 30 feet deep do not pass through it except 

 along the edge near the higher ground. At one locality, a mile 

 and a half south of Green Village, clay is reported to be over 



1 N. J. Geol. Surv., Vol. V, Report on Glacial Geology, pp. 616-619. 



2 N. J. Geol. Surv.. Ann Rep. for 1893, an d Vol. V. Report on Glacial 

 Geology. See, also, Plate X, in pocket, for the outline of Lake Passaic. 



