CLAYS OF BERGEN COUNTY. 375 



4 per cent., color red and the bricklet steel-hard, with absorption 

 of 2.03 per cent. The clay became viscous at cone 1, which shows 

 that it is of very low fusibility. It burns to a good hard brick, 

 however, at a low temperature. When molded in a dry press and 

 burned at cone 03 the fire shrinkage was 3.3 per cent., the ab- 

 sorption 5.33 per cent, and the color brownish red. The bricklet 

 was barely scratched. On account of the shaly character of the 

 material a number of hard grains remain after the grinding, and 

 these, at least when the clay is wet molded, interfere with the soft, 

 smooth surface of the brick. However, this is not sufficient to be 

 looked upon as a defect, but would be rather liked by many archi- 

 tects. So far as shown by these tests, it is doubtful whether the 

 material could be used successfully for the manufacture of paving 

 brick, since it softens rapidly in burning, and in making a vitrified 

 product, such as a paving brick, there might be some danger of 

 everburning and fusing the product. 



Clay-working industry. — The development of the common- 

 brick industry between Hackensack and Little Ferry is the second 

 most extensive in the State, ten firms manufacturing brick from 

 these clays (p. 267). Many million common brick are made here 

 annually by the soft-mud process, and with the yards all situated 

 along tide water the product can be easily shipped. The clays are 

 mixed with at least 25 per cent, sand, which is found immediately 

 underlying the surface and above the clay. A large area has been 

 dug over (Pis. XXXVIII and XXXIX), and some of the clay 

 pits have been dug to a depth of 60 feet. As indicated in Chapter 

 VI, these or similar clays occur over somewhat extensive areas 

 and have been observed at widely separated points. Common 

 brick and front brick are made by the Kingsland Brick Company, 

 at Kingsland, from the Triassic red shales. 



Art tile are made at Maywood, near Hackensack, but not from 

 any clays found in the county. 



