174 CLAYS AND CLAY INDUSTRY. 



between Sayreville and South Amboy. It is also found north of 

 the Raritan, in the high ground north of Eagleswood and Florida 

 Grove. It has not been recognized west of South river, although, if 

 present at all, it should occur in the high slopes bordering the 

 streami between South River village and Old Bridge. The upper 

 part of these slopes are, however, gravel (Pensauken) and the 

 lower are quartz sand, with some thin clay laminae. 



South of the Raritan and east of Sayreville the bed has a nar- 

 row outcrop along the lower slope of the hill. Since it dips gently 

 to> the southeast and the surface rises steeply in the same direc- 

 tion, the clay bed occupies but a narrow belt at the surface, and, 

 when followed into the hill, is soon deeply buried by the overlying 

 Cretaceous sands (No. 3) and the much more recent Pensauken 

 gravel. North of the Raritan the surface is more nearly level, or 

 slopes in the same direction as the dip of the clay bed, so> that the 

 latter occurs near the surface over a wider area. These facts are 

 shown on Plate XI, where the zone of outcrop is shown, as well 

 as the probable extension of the clay beneath the overlying beds. 



The South Amboy fire-clay bed is in general a white, light-blue, 

 or red-mottled clay. Locally some portions of the bed are quite 

 dark and contain bits of lignite. The following succession has 

 frequently been observed, beginning at the top : (a) Sandy white 

 to buff-colored clay, (b) blue fire clay, ,(c) sandy red-mottled 

 clay. These are not distinct layers, but gradations from top to 

 bottom in the one bed, and similar horizontal variations, fre- 

 quently occur. The upper and lower portions are often more 

 sandy than the middle part, but in at least two widely separated 

 localities, McHose Brothers (45) and J. R. Such (6y) t , one north 

 and the other south of the Raritan, beds of loose quartz sand, 

 varying from 2 to 12 feet in thickness, are known to occur in the 

 middle of this bed, separating the fire clay into a top and bottom 

 layer. Mr. Such also reports finding in one portion of his bank 

 a lense of fine clay in the middle of this intermediate sand layer. 

 It is apparent, therefore, that this clay bed shows considerable 

 variation in different banks. " 'Sulphur balls,' or round ball-like 

 aggregations of pyrite crystals, are found in many places in this 

 bed. They occur irregularly in all parts of it in the rich white, 

 or fine fire clays, just as in the inferior red clays. These are from 



