4o6 CLAYS AND CLAY INDUSTRY. 



CAPE MAY COUNTY. 



Clays are dug at only one locality in this county, viz., at Wood- 

 bine (Loc. 189), where they are worked into common building 

 brick by Bushnell & Westcott. The deposit lies 1-1^2 miles 

 southeast of the depot and not over one-eighth mile south of the 

 agricultural school. The clay is known to be 6 feet thick, under- 

 lain by sand, and covered by about 1 foot of sandy stripping. 

 It is, therefore, a comparatively shallow deposit. The material is 

 mostly quite sandy, but fairly plastic. It is usually red-burning, 

 but patches of whitish-burning clays are occasionally found, one 

 of these occurring at the north end of the bank. The latter is 

 bluish-white in color and is usually avoided in mining. 



Plate XLIII, Fig. 1, shows one portion of the pit, and indicates 

 well the thickness of the clay, thin overburden, and dense brush 

 growth on the surface. The two latter interfere somewhat with 

 the search for clays in this region, and, therefore, careful pros- 

 pecting with an auger is very necessary. 



The physical characters of the run of the bank (Lab. No. 705), 

 as shown by the green brick mixture, are as follows : Water re- 

 quired for tempering, 21.4 per cent. ; air shrinkage, 4.3 per cent. ; 

 average tensile strength, 90 pounds per square inch. 



Bunting test of brick mixture, Woodbine. 



Cone 1 Cone 10 



Fire shrinkage, 1% 3-7% 



Color, red gray brown 



Condition, steel-hard 



Absorption, 12.77% 



The bluish-white clay (Lab. No, 678) is tough, gritty and mod- 

 erately plastic. It takes more water than the other, viz., 27.8 per 

 cent., and its air shrinkage is also higher, being 6 per cent. On 

 firing the brick seems to expand, possibly due to high silica con- 

 tents and also to fusion. This is shown below : 



