494 CLAYS AND CLAY INDUSTRY. 



SALEM COUNTY. 



This county extends from the Delaware river in- a southeast 

 direction to> the Maurice river, a distance of about 27 miles. It, 

 therefore, might include clays belonging to the Raritan, Clay 

 Marl, Alloway, Cohansey and Cape May formations, but some 

 of these are not exposed on account of the heavy capping of sur- 

 face materials. The Alloway clay is the only important deposit 

 exposed and worked. 



Pentonvitle. — The Cape May has been opened to supply a small 

 brickyard at Pentonville (Loc. 166), but the deposit is a shallow 

 one, from 2 to 4 feet in thickness, and is underlain by sand. It 

 burns to a red color and is quite porous at the temperature reached 

 in common-brick kilns. The Cape May clays have also been 

 worked for brick at Salem. 



Alloway Ciay. 



The Alloway clay is the most important clay deposit in this 

 county, and it was examined at a number of localities. Its extent 

 is shown in detail on the map, Plate XIII. 



Yorktown. — The most extensive opening, although not a very 

 deep one, is seen at the brickyard of David Haines, south of 

 Yorktown (Loc. 162, PI. LV). The clay bank forms a long, 

 shallow excavation to the west of the yard, and exposes an upper 

 and lower bed of clay, covered by loam which is in part gravelly. 



If the pit is followed from east to west it is found that the 

 sandy overburden increases in thickness. The upper clay bed is 

 a whitish clay with yellow mottling, containing occasional seams 

 or crusts of limonite (PI. II, Fig. 2), and varies from 8 to 15 

 feet in thickness. The under clay is a blue, very plastic material, 

 of great cohesiveness. It is said to run 50 feet in depth, and was 

 bored into for a distance of 8 feet to obtain a sample. 



At the western end of the clay bank the sand is found ap- 

 parently to rest directly on the blue clay, as if the mottled clay 

 had thinned out. This apparent fading out of the one bed is due 



