194 CLAYS AND CLAY INDUSTRY. 



and at the Dixon bank in Woodbridge by M. D. Valentine & 

 Bros. (9). It was also formerly dug on the Ellison property, 

 southeast of Edgar's banks (94). Here a pit passed through the 

 following section : 1 



Section in a pit on the Ellison property. 



(1 ) Sand, coarse, and in part a fire sand, 7 ft. 



(2) "Hard pan" of sand, cemented by oxide of iron,. ... 1 



(3) Clay, 8 " 



(4) Clay and lignite, 2 " 



(5) "Hard pan" layer (cemented sand), ij4 ' 



(6) Clay, 4-4^ " 



The upper clay (3) was a fire clay; the lower clay a potter's 

 or terra-cotta clay. The sand bed between them separates the 

 fire clay above, from the potter's clay below, so> that here they 

 apparently occur in two' well-defined beds. 



The potter's clay: — The Raritan potter's clay of the earlier re- 

 port, which at Ellison's bank underlies the fire clay and apparently 

 constitutes the lower part of this clay member, is extremely vari- 

 able in color and in composition. It is often a white or white- 

 blue clay ; elsewhere it is a red-spotted clay, and its basal portion 

 is usually a deep chocolate red, closely resembling the decomposed 

 shale from, which it was doubtless in part derived. 



It has been found beneath the fire clay only on the old Ellison 

 property ; elsewhere, so far as exposed, it occurs without the fire 

 clay, being directly overlaid, either by the much later Pleistocene 

 deposits (glacial drift, or Cape May sand and gravel) or less fre- 

 quently by the fire sand ( Sand No. 1 ) . In the former case the 

 absence oi the fire clay may be assumed to be due to> erosion in the 

 long interval between Cretaceous and Pleistocene times. In the 

 latter case, it may be that the fire clay was never deposited, or 

 that it was eroded away by the swifter currents, which attended 

 deposition of the overlying fire sand. Over the larger part of the 

 area mapped as the Raritan fire and potter's clay, Plate XI, only 

 the potter's clay occurs, so far as present data show. 



At the present time it is dug only by the Brinckman Terra 

 Cotta Company (96) east of Martin's dock, and by Augustine 



1 Idem, p. 167. 



