CLAYS OF MIDDLESEX COUNTY. 459 



Stoneware Clay. 



The No. 2 stoneware clays are probably all semirefractory, but 

 fusion tests were made on only three of them. 



In the Woodbridge district one sample from locality 21, P. J. 

 Ryan, was found to become thoroughly viscous at cone 30. 



Although some of the clays mined in the areas between Wood- 

 bridge and Metuchen may be used in stoneware mixtures, none 

 are marketed under that name. South of the Raritan river the 

 South Amboy stoneware-clay bed is of importance and supplies 

 several grades. A sample of No'. 1 clay has been described under 

 the refractory clays. The following represents a test on a No. 2 

 grade from H. C. Perrine & Son's "poorhouse bank" (Loc. 81, 

 Lab. No. 395). This clay in its raw condition showed much fine 

 grit and worked up to a plastic-feeling mass with 37 per cent, 

 water. Its tensile strength ranged from 108 to 120 pounds, with 

 an average of 109 pounds per square inch, and the air shrinkage 

 was 7 per cent. It was fired with the following results : 



Burning tests of a No. 2 stoneware clay, H. C. Perrine & Son. 



Cone 01 1 3 10 



Fire shrinkage, 6% 6% 7.6% 9% 



Absorption, ir.65% 8.77% 9-95% .24% 



Color, yellowish white light buff light buff gray buff 



At cone 1 the bricklet was steel-hard, at cone 27 clay incipiently 

 fused and became viscous at cone 30. 



The No. 2 stoneware clay from South Amboy (Loc. yy) fuses 

 at cone 27. 



Pipe Clay. 



At Crossman's pits at Burt Creek a variety termed pipe clay 

 is dug. A sample was collected (September, 1901) from a 

 pit close to the highway, in which the clay was covered by little 

 stripping (Loc. 64). The pit is shown in Plate L, Fig. 2. The 

 section showed 6 feet of pipe clay underlain by 6 feet of fine 

 quartz sand. The clay was a tough, yellowish-white clay, stained 



