532 CLAYS AND CLAY INDUSTRY. 



The areas in which clays of Cape May and Pensauken age 

 occur are not indicated since these formations are so irregularly 

 distributed, and lie upon those already mentioned. Nor has it 

 been practicable to map the clay-loam deposits which mantle many 

 of the older formations. Their general distribution is referred to 

 in the text. 



Plate Xa. — This map shows i) the location of all clay pits 

 which were visited in the course of this investigation, 2) many 

 localities where clay is known to occur but is not worked, and 3) 

 the distribution of the various kinds of clay manufactures 

 throughout the State. 



The numbers are the locality numbers used in the text of the 

 report. By reference to the index all important data respecting 

 the clay at each of these localities can be found. Since the red 

 circle is carefully marked on the map at the place where the clay 

 was observed, all the deposits can be located in the field by anyone 

 at any time. 



No attempt has been made to plot all the occurrences of clay 

 in the State. Doubtless some, particularly in the pine belt, where 

 sand covers the surface, have been omitted. 



The various grades of clay ware manufactured are indicated 

 by different symbols, which are explained in the legend on the 

 map. Their position does not indicate the exact location of the 

 factory, but they are placed near the name of the town, which is 

 itself underscored in red. 



Plate XL — The clay deposits of northeastern Middlesex county 

 are shown on this map. The attempt has been made, not only 

 to represent the belts where the various clay beds occur at the 

 surface, or are only thinly covered, but also their probable ex- 

 tension beneath thicker beds of sand or gravel, and the limits 

 within which they are probably available. The differences in 

 pattern used to accomplish this result are shown in the legend 

 on the map. There is no question but what the clays extend 

 far beyond the limits thus marked, and underlie much of the 

 area left uncolored, particularly south of the Raritan river, but 

 in these districts they are buried so far beneath the surface that 

 only occasional deep wells penetrate them, and they are com- 

 mercially valueless. On the southeastern part of the map, the 



