THE MIXING AND QUARRY INDUSTRY 917 



The Cummings Cement Co., which is listed among the manufac- 

 turers of natural rock cement, has been a producer also of Portland 

 cement though it made no output of that material last year. 

 The Helderberg Portland Cement Co. produces both kinds. The 

 firm of Spencer & McCarthy was succeeded on April i, 1904, by 

 the Jamesville Milling Co. The Empire, Hudson and Glens Falls 

 Portland cement plants were operated for a part of the year only. 



CLAY 



The manufacture of brick and other clay products is the most 

 important branch of the mineral industry in New York. Clay 

 deposits suitable for making the common wares are distributed 

 throughout every section in practically inexhaustible quantities 

 The rapidly growing market for these products has led to the 

 establishment of numerous manufacturing plants in recent years, 

 so that now there is scarcely an industrial center of any size in 

 which they are not produced. This is particularly true with 

 regard to the manufacture of building materials, which are being 

 employed more and more widely as an element in permanent 

 construction. Owing to their cheapness, durability and the 

 convenience with which they can be adapted to meet the varied 

 architectural requirements, the use of these materials will doubtless 

 continue to expand for a long time to come. 



The manufacture of the finer grades of clay wares has not de- 

 veloped so rapidly as the other lines. In contrast with most 

 of the states along the Atlantic seaboard, New York possesses 

 almost no deposits of kaolin in quantity to be of economic value. 

 This fact has retarded, hitherto, the establishment of industries 

 in which kaolin is employed, but, with improved facilities of 

 transport, the deficiency has become less formidable to local 

 manufacturers. There are now several plants in the State making 

 tableware, electrical supplies and other porcelain and semipor- 

 celain wares. 



The distribution of clays in New York as well as their character , 

 uses and industrial development has been exhaustively described 

 in a report by Heinrich Ries\ to which the reader is referred for 

 fuller details. The most valuable deposits now under exploi- 

 tation are those situated along the Hudson valley. They are 

 particularly adapted for the manufacture of brick, of which great 

 numbers are consumed in New York city. According to Dr Ries, 

 the deposits belong to two types: (i) estuary deposits of strati- 



iN. Y. State Mus. Bui. 35. 1900. 



