CLAYS OF CUMBERLAND COUNTY. 409 



Amount of water necessary to temper, 32.3 per cent. ; air shrink- 

 age, 4 per cent. ; average tensile strength, 163 pounds per square 

 inch. Its behavior in burning was as follows : 



Burning tests of clay from Clayville, near Vineland. 



Fire shrinkage. Color. Absorption. Condition. 



Cone 03, 4-6% yellowish white 13.07% 



1, 7.3% buff 6.14% steel-hard 



3, 8.0% buff 8.34% 



8, 10.0% green gray 0.42% 



10, 8.0% gray 0.46% 



15, 7-3% gray 2.64% slightly blistered 



and swelled 



Chemical analysis of clay, Clayville, 



Silica (SiOo), 66.12 



Alumina ( A1 2 3 ) , 22.07 



Ferric oxide (Fe?0 3 ), 1.31 



Lime (CaO), 0.50 



Magnesia (MgO), 0.25 



Alkalies, (Na 2 0, K 2 0), i.81 



Water (H 2 0), : 7-94 



100.00 

 Total fluxes, 3%7 



The clay has been used for electrical conduits, fireproofing and 

 buff brick. It could also be employed in terra-cotta manufacture, 

 but it is not a fire clay. 



Millville. — Another series of pits were found nearer to Mill- 

 ville. The most westerly of these is a 4-foot opening in a bed of 

 sandy clay along the road west of Millville on the way to Bridge- 

 ton (Loc. 182). The locality is known as the old Wood's pit, 

 and is not being worked. As far as could be determined the. 

 deposit is more than 4 feet thick and probably not less than 10, 

 with 2 feet of gravelly overburden. The deposit lies immediately 

 adjoining the main highway and has fairly good haulage facilities. 



A partial test was made of it (Lab. No. 661) to* determine 

 approximately its character with the following results: Water 

 required 36.4 per cent. ; air shrinkage, 6.6 per cent. ; average 

 tensile strength, 286 pounds per square inch. 



