CLAYS OF ATLANTIC COUNTY. 369 



ATLANTIC COUNTY. 



Most of the deposits worked in this county belong to the 

 Cohansey formation, and opening's have been made near Bakers- 

 ville, Da Costa, Elwood, Egg* Harbor City and Mays Landing. 

 At Bakersville there are extensive deposits which seem best re- 

 ferred to the Cape May, although perhaps they belong to the 

 Cohansey. In nearly every instance the occurrences represent a 

 more or less basin-shaped deposit, covered by sand, and lying in 

 a flat region covered with a thick growth of underbrush. 



Da Costa. — Beginning at the northwestern side of the county 

 the first deposit seen was south of Da Costa at the brickyard of 

 David Doerr (Loc. 197), where the pit shows the following 

 section : 



Gravelly loam, 2-4 ft. 



Yellowish-gray clay, underlain by some black clay, 9 



Sand, 



The clay, which is mostly red-burning, shows occasional streaks 

 of sand, which are sometimes cemented by limonite, and, if these 

 get into the bricks, they are liable to cause fused spots. The 

 lighter-colored, as well as lighter-burning clay, forms irregular 

 patches here and there in the deposit and is not much used in the 

 bricks. Two openings have been made, indicating that the 

 length of the deposit is probably not less than 300 feet. The run 

 of the bank, excluding the light-burning material, was obtained 

 by taking a sample by boring to a depth of 5 feet, with an ad- 

 ditional 4 feet from the sides of the pit. 



This clay showed the following physical characters. Water 

 required for tempering, 30.8 per cent. ; air shrinkage, 6.6 per cent. 

 Average tensile strength 206 pounds per square inch. Its be- 

 havior in burning was as follows : 



Burning tests of clay of David Doerr from Da Costa. 



Cone 05 



Fire shrinkage, 0.7 % 



Absorption, 16.56% 



Color, pink red 



Condition, not steel-hard 



24 (X G 



Cone 1 



Cone 3 



Cone 5 



2 % 



4 % 



4 % 



15.72% 



10.87% 



8-34% 



light red 





red 



not steel-hard 





steel-hard 



