158 CLAYS AND CLAY INDUSTRY. 



II, or the Woodbury clay, from the fact that it was well exposed 

 in the railway cut at that place. 1 The clay is somewhat mica- 

 ceous, black in color, not sandy in the lower portion, but slightly 

 so in the upper part, where it is locally distinctly laminated. It 

 does not contain glauconite except perhaps at the very base, and 

 in this respect it is to be distinguished from Clay Marl I, a glau- 

 conitic clay which underlies it. It weathers to a dove or light 

 chocolate clay, which, when dry, breaks into' innumerable blocks, 

 large and small, frequently with a conchoidal fracture (PI. 

 XVIII, Fig. i). In some localities, as at Dobbs' clay pit, near 

 Camden (144), these joint faces are smoothed and polished in a 

 striking manner. In its lower portion it is penetrated by numer- 

 ous joints. Many of these are filled with crusts of limonite, which 

 sometimes form huge honeycomb masses many feet in diameter 

 and tons in weig'ht. A most striking case of this sort was ob- 

 served on the north bank of Rancocas creek west of Rancocas, 

 where the clay was found to be so filled with these limonite 

 masses as to render it necessary to' abandon an extensive brick- 

 making plant. 



Although the upper portion is more sandy than the lower, it 

 is quite sharply set off from the sand bed above, the transition 

 layer being only two or three feet in thickness at the most. Its 

 base also is fairly distinct, although since the underlying member 

 is also a clay bed, this line is not so sharp as at the top. This 

 clay varies from 55 feet in Monmouth county to something less 

 than that along the Delaware. 



Although this member presents slight local variations, yet 

 it can be readily traced across the State and is easily recognized 

 by its characteristic features ; i. e., its dove or light-chocolate 

 color when weathered, its many joints, its. lack of marl and its 

 position beneath the sand bed (Clay Marl III). Its characters 

 are such that there is no question of its integrity as a definite 

 and distinct bed at any point between the shores of Raritan bay 

 and the Delaware river in Salem county. 



Localities. — The position of this clay bed in the vicinity of 

 Matawan is shown in detail on Plate XII. Within this area 



1 This exposure has recently been obscured by grading, but numerous out- 

 crops occur along the banks of the creek a mile west of Woodbury. 



