66 NEW YORK STATE MUSEUM 



Lead lake has been estimated at 100,000 cubic yards and that in 

 Clear lake at about the same amount; the deposits in Roilly pond 

 and Big Crooked lake, according to Mr Cox, may contain over 

 1,000,000 cubic yards each. About 5 acres of the filled lake or 

 Beaver meadow west of Big Crooked lake is said to be covered by 

 a deposit from 2 to 12 feet thick, with an average depth perhaps 

 of 3 feet. Overlying this bed is about i foot of soil and vegetable 

 matter. The earth at all the localities consists of an aggregate 

 of different kinds of diatoms, mostly of the unattached or free forms. 

 The ponds and lakes came into existence after the retreat of the 

 Pleistocene ice-sheet. 



According to F. J. H. Merrill, diatomaceous earth is present on 

 the shore of Cold Spring Harbor, Long island, notably on property 

 owned by Dr Oliver Jones. It is stated to be of fossil nature, as it 

 occurs in beds that are regarded as Tertiary in age. 



References 

 Cox, Charles F. On Recently Discovered Deposits of Diatomaceous Earth in 



the Adirondacks. N. Y. Acad. Sci. Trans., v. 12, 1893, p. 219-20 

 Additional Notes on Recently Discovered Deposits of Diatomaceous 



Earth in the Adirondacks. Op. cit., v. 13, 1893, p. 98-101 

 Merrill, F. J. H. Mineral Resources of New York State. N. Y. State Mus. 



Bui. 15, p. 555-56 



EMERY 



Conditions in the emery trade during the last year or two have 

 encouraged the further development of the local supplies, and the 

 output of the mines in the Peekskill district has assumed increased 

 proportions, representing an important share of the emery available 

 for consumption in this country. 



Aside from New York State, Massachusetts and Virginia contain 

 emery deposits that possess, or have possessed commercial value. 

 The deposits at Chester, Mass., once supplied considerable quan- 

 tities, but have been inoperative for some time and may not enter 

 the market again. Virginia has contributed smaller quantities from 

 an occurrence near Whittle Station, Pittsylvania county, where, it 

 is reported, operations were under way last year. The Peekskill 

 deposits have been worked continuously for the last 20 years and 

 were operated in a desultory manner for an additional period of 

 several years. Altogether they have yielded probably about 70,000 

 tons, of which amount over one-half has been taken out in the last 

 three years. 



The incentive for the recent growth of mining in the Peekskill 

 district is to be found in the practical elimination of foreign emery 



