64 NEW YORK STATE MUSEUM 



Among the miscellaneous articles which have been made by New 

 York potteries in recent years are art wares, delft, chemical and 

 sanitary wares, and tobacco pipes. 



The pottery production for 191 7 was valued at $4,076,817, about 

 one-half of which represented the value of porcelain electrical sup- 

 pHes ($2,018,363) and over one-third of the total consisted of china 

 table wares ($1,574,962). Ini9i8 the pottery production amounted 

 to $6,047,472, of which $3,595,478 is credited to porcelain electrical 

 supplies. 



References to clay 

 Beck, Lewis C. Mineralogy of New York. 1842 

 Bishop, Irving P. Structural and Economic Geology of Erie County. N. Y. 



State Mus. 49th Ann. Rep't, v. 2, 1898 

 Hall, James. Geology of New York. Survey of the Fourth Geological District. 



1843 

 Jones, R. W. The Manufacture of Paving Brick in New York State. N. Y. 



State Mus. Bui. 174, 191 4, p. 23-31 

 Luther, D. Dana. Economic Geology of Onondaga County. N. Y. State Mus. 



49th Ann. Rep't, v. 2, 1898 

 Nason, F. L. Economic Geology of Albany County. N. Y. State Mus. 47th 



Ann. Rep't, 1894 

 Ries, H. Clays of New York, Their Properties and Uses. N. Y. State Mus. 



Bui. 35, 1900 

 Physical Tests of the Devonian Shales of New York State to Determine 



their Value for the Manufacture of Clay Products. N. Y. State Mus. 49th 



Ann. Rep't, v. 2, 1898 



Quaternary Deposits of the Hudson River Valley between Croton and 



Albany, etc. N. Y. State Geologist loth Ann. Rep't, 1891, p. 110-55 

 Geology of Orange County. N. Y. State Mus. 49th Ann. Rep't, v. 2, 



1898 

 Woodworth, J. B. Pleistocene Geology of Nassau County and Borough of 

 Queens. N. Y. State Mus. Bui. 48, 1901 



DIATOMACEOUS EARTH 



Diatomaceous earth is a finely divided earthy substance that 

 closely resembles chalk or marl in appearance but has a base of 

 silica instead of lime carbonate. It is an accumulation of the skeletal 

 remains of minute organisms (diatoms) that live in fresh lakes and 

 ponds. It is sometimes called tripoli, but the two should not be 

 confused, as tripoli is a silicous earth formed by the decomposition 

 and breaking down of impure limestones and hence of inorganic 

 derivation like rotten stone. It is a very light, porous, usually 

 white material that occurs in powdery or slightly coherent condition. 

 Chemical analysis shows the presence of considerable water com- 

 bined with the silica, so that it differs from ordinary quartz and is 



