47o CLAYS AND CLAY INDUSTRY. 



gravel, and also scattered particles of lignite. Some of the pits 

 show thin streaks of clay. These fire sands are highly siliceous 

 in their composition, carrying from 92.5-98.00 per cent, of silica, 

 as shown by Dr. Cook's analyses, and 1.45 to 6.65 per cent, of 

 alumina and iron oxide. 



CLAY-WORKING INDUSTRY. 



It is but natural that with such an abundance of raw materials 

 in Middlesex county, there should be a thriving local industry 

 supported by them, even though much of the material mined is 

 shipped to other counties and even other States. The clay 

 products of the county include common, pressed, enameled, and 

 paving brick, terra cotta, wall tiles, fire brick, hollow brick, fire- 

 proofing and conduits. The common-brick industry is developed 

 chiefly in the region around Sayreville and South River, 1 where 

 the vast deposits of black, laminated sands and clays are exten- 

 sively worked for making common soft-mud brick. Large open- 

 ings have been made, and the clays are often dug with steam 

 shovels. These clays yield a product of very good quality, which 

 is extensively shipped to the neighboring cities for building pur- 

 poses. The pressed brick made in this region are obtained to a 

 small extent by re-pressing the common red brick, but the large 

 majority of them are made from a mixture of the several grades 

 of fire clay. Their various shades and mottlings are produced in 

 part by the manipulation of the kiln fires, and in part by the addi- 

 tion of artificial coloring matter. These bricks are made chiefly 

 ;at Sayreville, although some have also been produced at South 

 River, but the factory there is no longer in operation. Enameled 

 bricks are produced by the American Enameled Brick & Tile Com- 

 pany, of South River, and the Sayre & Fisher Company, of 

 Sayreville. Next to the common-brick industry along the Raritan 

 river, the hollow-brick industry occupies a very prominent posi- 

 tion, and the clays used for this purpose belong to the same bed 



1 Several large yards are also located near the county line, not far from 

 Cliff-wood, Monmouth county. These are described with the Monmouth 

 county clays. 



