336 CLAYS AND CLAY INDUSTRY. 



the factories requiring clays of medium or high refractoriness, to 

 buy their materials from a number of clay miners. 



Furthermore, the terra-cotta, fire-brick, and tile factories and 

 potteries located in adjoining States are often not able to obtain 

 their raw materials near the works, and draw upon New Jersey 

 for a large portion of their supply. 



The result of this has been that in several areas of New Jersey, 

 chiefly within the Raritan clay belt, a thriving clay-mining indus- 

 try has been developed. These areas are, i) the Middlesex 

 county area, including the region around Woodbridge and South 

 Amboy; 2) the Trenton area; 3) the Delaware river area; 4) 

 the Woodmansie area. 



MIDDLESEX COUNTY. 



In the northeastern portion of Middlesex county, especially 

 around the towns of Woodbridge, Perth Amboy, South Amboy, 

 Sand Hills, etc., there is developed the most important clay min- 

 ing area in the State, the deposits in this region having been 

 worked for a number of years. The importance of this area is due 

 in large degree to> the vast quantities of the higher grades of clay 

 which have been obtained there, 1 ease of extraction and good 

 transportation facilities by water or rail. 



The output from this region is contributed by between twenty 

 and thirty firms or individuals. Around Woodbridge and Perth 

 Amboy, especially, many acres of clay land have been dug over 

 and the operations carried on since the early part of the nineteenth 

 century. In the earlier years of the clay-mining industry, it was 

 chiefly the better grades of clay that were sought for, and in order 

 to> obtain these, many beds that were then of no commercial value, 

 but for which there would now often be a call, were thrown 

 aside or mixed with overburden, so that through these v/asteful 

 methods much good material was lost. At the present day more 

 care is exercised, and in some cases even filled pits are being 

 re-excavated to get the clay that was left at the bottom. 



1 See description of Middlesex county, Chap. XIX. 



