434 CLAYS AND CLAY INDUSTRY. 



MIDDLESEX COUNTY. 



Importance. 



Clay-bearing formations. 

 Method of classification. 

 Highly refractory clays. 



Fire clays. 



Ball clay. 

 Refractory clays. 



Fire clays. 



Woodbridge. 



Florida Grove. 



Sand Hills and Bonhamtown. 



Burt Creek. 



Ball clay. 



Stoneware clay. 

 Semirefractory clay. 



Fire clay. 



Fire-mortar clay. 



Stoneware clay. 



Pipe clay. 



Miscellaneous. 

 Nonrefractory clays. 



Woodbridge. 



North side of the Raritan river. 



Sayreville. 

 Feldspar. 

 Fire sands. 

 Clay-working industry. 



IMPORTANCE OE THE COUNTY. 



This is the most important clay-producing county in the State 

 of New Jersey, and its importance was so' marked even at an 

 early date that in 1878, it was made the most prominent part of 

 the Report on Clays issued by the New Jersey Geological Survey. 

 Indeed, so extensively is the clay-working- industry of Middlesex 

 county developed, that it is highly probable that the value of the 

 clay products manufactured there, together with the value of the 

 clay mined by persons other than manufacturers, forms about 

 35 per cent, of the total value of the New Jersey clay-working 

 industry. 



Although the county is of large size, still the industry shows a 

 peculiar degree of concentration, being centered in its north- 

 eastern corner. 



