360 CLAYS AND CLAY INDUSTRY. 



The fire shrinkage at cone 05 ranged from 0.4 up to 4.7 per 

 cent., being greatest in the most dense-burning samples. At cone 

 1 there was, however, less variation among the different samples 

 than at cone 05, the majority showing between 4 per cent, and 5 

 per cent, fire shrinkage. One sample from north of Matawan 

 (Loc. 23 1 ) shows a fire shrinkage of 8.7 per cent, at cone 1 . Very- 

 few of the clays of this formation become viscous below cone 10, 

 but they are not semirefractory. One from a locality along 

 Matthew's brook, 1 mile south of west of Woodbury (Loc. 

 157), became viscous at cone 8. This same clay warped consid- 

 erably at all the temperatures at which it was burned. 



Uses. — The deposits of Clay Marl II are at present used either 

 alone or with other clays at nine localities, so- far as known. They 

 are worked at Crosswicks for the manufacture of draintile and 

 hollow bricks ; at Hightstown in connection with a surface clay 

 for making stiff-mud brick ; at Collingswood for brick and drain- 

 tile; at Lorillard, near Keyport (224), for fireproofing ; at 

 Matawan (228) for brick (with Clay Marl I) ; at Jamesburg 

 (295) for brick; at Maple Shade (149 and 150), for brick (both 

 alone and with Clay Marl I). The only place where the material 

 is dug for pottery manufacture is near Matawan, and there the 

 weathered part of the deposit is mined and made use of for red 

 earthenware flowerpots. It is highly probable that some of the 

 other occurrences could be used for the manufacture of earthen- 

 ware. There seems no good reason why these clays should not be 

 re-pressed for front brick. No buff-burning clays or fire clays are 

 to be looked for in this formation. 



CLAY MARL I. 



The exposures of Clay Marl I sometimes occur along streams 

 and are favorably located for working as banks with the easy 

 maintenance of proper drainage, but at other times the bed has to 

 be worked as a pit and drained by pumping. Clay Marl I is dark- 

 colored, lean-feeling clay with much organic matter, coarse sand, 

 mica (Figs, 32, 33) and green grains of glauconite, but the 

 weathered outcrops are sandy and colored cinnamon brown. The 



