1 62 CLAYS AND CLAY INDUSTRY. 



definite and orderly arrangement over extended areas. Individual 

 beds of clay thin out rapidly or grade bodily into beds of sand 

 within short distances. In not a few instances data have been 

 observed, which indicate that beds after deposition were partially 

 swept away by shifting currents, before the overlying layers 

 were formed. Within comparatively short distances, also, sand 

 and clay were being deposited simultaneously, so that rapid 

 changes in the character of the deposit have resulted. In these 

 respects the Clay series is in marked contrast to the Clay Marl or 

 Marl series, during the deposition of which uniform conditions 

 prevailed over wide areas, and successive deposits were formed, 

 which can be traced as individual beds across the State. 



Although it is impossible to establish any divisions in the 

 Raritan series, which can be accurately identified at widely sepa- 

 rated intervals, nevertheless, as was long ago pointed out by Cook 

 and Smock, 1 in Middlesex county, in the vicinity of Woodbridge, 

 Perth Amboy, South Amboy and South River, where the beds 

 have been extensively opened in many localities, there are cer- 

 tain divisions, which in their general features persist from open- 

 ing to opening, and so can be traced through all the region. Yet 

 even here, not infrequently many of the minor beds seen in one 

 pit are wanting in the next one a few rods away, showing that 

 variable conditions prevailed, even in this area. 



The degree, however, to which the Clay series has been sub- 

 divided in this part of Middlesex county is probably not due 

 entirely to the distinctness and persistence of individual mem- 

 bers. The great number of exposures, both natural and artificial, 

 enable one to trace the beds with much greater detail than in any 

 other portion of the State. Were the formation everywhere so 

 well exposed as in this region, it is highly probable that some 

 similar classification could be made in other districts., and that 

 the formation would not prove to be such a varying complex of 

 clay and sand, as seems to be the case. It is certain, however, 

 that the classification which is applicable to Middlesex county- 

 would not apply to Burlington, and it is equally certain that no 



1 Report on the Clay Deposits ef Woodbridge, South Amboy, etc., 1878, 

 PP- 33-75- 



