CLAYS OF CRETACEOUS FORMATION. 185 



or "ironstones'' are not uncommon at some horizons, and are 

 locally so abundant as to form an almost continuous layer of stone. 



At many banks these layers have to be removed in order to get 

 at the fire clay. They were formerly thrown away in great part, 

 and this is to some extent the case at present, but most of them can 

 be used in hollow brick, fireproofmg, common brick, etc., and at 

 many points, particularly near Maurer, Keasbey, Sayreville and 

 South River, they are so used very extensively. 



These clays, where uneroded, vary from 30 to> 60 feet in thick- 

 ness, according as it is possible to* differentiate certain beds just 

 above the fire clays, or as all beds down to the fire clays are in- 

 cluded. 



In the area about Woodbridge the black laminated clays are 

 shown in the upper part of the banks worked by M. D. Valentine 

 & Bros. (14). J. H. Leisen (16), Anness & Potter (6), Perth 

 Amboy Terra Cotta Company (7), P. J. Ryan (8), W. H. Cutter 

 (29, 30), and James P. Prall (28, 31), while the banks near 

 Maurer Station, i. c, of the Staten Island Clay Company (33, 

 43) and of Henry Maurer & Son (36, 34), are entirely in this 

 member. 



In the Sand Hills area, the black laminated clays are well ex- 

 posed in the bluff west of Florida Grove and in the banks of the 

 Perth Amboy Terra Cotta Company (241), the Standard Fire- 

 proofing Company (46, 47), the International Clay Company (48, 

 49), Henry Weber (52), Mrs. John Goodrich (51), Ostrander 

 Fire Brick Company (53), R. N. & H. Valentine (55, 86), D. A. 

 Brown (87), and Charles Edgar (94), near Bonhamtown. 

 South of the Raritan river they occur along the shore from Kear- 

 ney's dock southwest to Crossman's dock, where the upper beds 

 are dug. At Sayreville, the black clays dug by the Sayre & Fisher 

 Company (71), William F. Fisher (74), Edwin Furman (72), 

 and Boehm & Kohlhepps (73), for common brick, belong to this 

 member. In the vicinity of South River and Milltown, they are 

 found in the banks of Jos. Bissett (85), Yates Brothers (82), 

 Theodore Willets (83), John Whitehead (84), Pettit & Co. 

 (247, 249), National Clay Manufacturing Company (244), N. 

 A. Pyrogranite Company (246), M. A. Edgar (252), and the 

 Sayre & Fisher Company (253, 254). 



