ECONOMIC GEOLOGY 227 



commercially at present. The material is dug from the bottom 

 of the lake, which covers about four acres, and has a thickness of 

 two to 30 feet, being covered by about four feet of water. It 

 is washed and run through strainers and pipes to settling vats, 

 where it stands for 24 hours. The water is then drawn 

 off and the material shovelled into the press. Here it is made 

 into cakes four feet square and four inches thick. These are 

 subdivided into cakes one foot square and piled under sheds to 

 dry. For this information I am indebted to the proprietor, Mr. 

 Thomas W. Grosvenor, of Herkimer. 



The White lake material is at present only used for polishing, 

 though similar material is used for absorbing nitroglycerine in 

 the manufacture of dynamite. 



Talc 



This material occurs near Edwards, St Lawrence county, 

 N. Y., in a narrow belt several miles long and about a mile wide. 

 There are several quarries on the line of this belt. It is ground 

 in mills near Gouverneur under the control of the Asbestos Pulp 

 Company. It is chiefly used in the manufacture of paper and a 

 small quantity is used in soap, paint and other minor purposes. 

 The annual product is about 30,000 tons, valued at about f 240,000. 



Peat 



This material, which is the residue from the partial decay of 

 plants in water, is of frequent occurrence, but is only used locally 

 as a fertilizer. , 



Petroleum and Illuminating Gas 



The occurrence of petroleum in New York was first recorded 

 by a Franciscan friar who visited the oil spring at Cuba, 

 Allegany county, in 1627. Late in the present century the oil 

 from this spring was highly valued by the Indians for external 

 applications and was thought to have a highly curative power. 

 It was widely known under the name of ' Seneca oil.' The pro- 

 duction of oil in New York is at present confined to Cattaraugus 



