498 CLAYS AND CLAY INDUSTRY. 



at Yorktown, and covered by not more than 2 feet of pebbly loam. 

 The outcrop is well located on account of the thin stripping, dry- 

 ness of the deposit and good drainage. The material (Lab. No. 

 688) required considerable water to temper it, viz., 48.7 per cent., 

 and had a high air shrinkage of 1 1 per cent. Its tensile strength 

 was low, being 80 pounds per square inch. It burned quite dense, 

 however, for at cone 1, with a fire shrinkage of 5.6 per cent., its 

 absorption was 5.18 per cent., and at cone 5, with a fire shrinkage 

 of 8.3 per cent., it absorbed only 0.46 per cent, of water. It be- 

 came viscous at cone 12. It burned red at cone 1, brown at cone 

 5, and gray at cone 8. A dry-press tile was burned at the last- 

 named cone, and showed 13.3 per cent, total shrinkage, which of 

 course occurred mostly in the firing. 



The Alloway clay outcrops again along the road opposite a 

 farmhouse, at a point one-half mile east of Alloway (Loc. 163). 

 Its thickness is more than 7 feet, the upper 5 feet being a light,, 

 sandy clay, while the lower 2 feet had occasional sand streaks. 

 The clay (Lab. No-. 685) worked up with 26.5 per cent, of water, 

 and had an air shrinkage of 8 per cent. Its tensile strength was 

 excellent, averaging 246 pounds per square inch. Its fire shrink- 

 age was low, being o per cent, at cone 05, 2 per cent, at cone 3, 

 and 5.3 per cent, at cones 5 and 8. Its absorption at these cones 

 was 16.59 P er cent., 10.57 P er cent., 4.51 per cent, and 6.39 per 

 cent., respectively. It was viscous at cone 27. 



It burned red up to cone 5, and a gray brown above that. Its- 

 fire shrinkage was somewhat lower than that of most of the other 

 Alloway clays. 



Richmanville. — Other outcrops of Alloway clay occur at Rich- 

 manville, along the bank of the stream (Loc. 160). The clay, as 

 determined by boring, extends at least 7 feet below the stream 

 level, and an additional thickness of 5 feet is exposed in the bank. 

 The overburden of gravel and sand increases in thickness as one 

 recedes from the stream. The clay even below stream level is 

 comparatively dry, and on the outcrop it dries and breaks up into 

 irregular fragments looking- not unlike those of Clay Marl IL 

 The sample (Lab. No. 675) was a smooth, very dense, dark- 

 colored clay of low plasticity, and fairly free from grit. It took 



