THE MINING AND QUARRY INDUSTRY I9IO 59 



SLATE 



The quarrying of slate in New York is restricted at present to a 

 siiiail district in eastern Washington county. The district extends 

 north from Salem through the towns of Hebron, Granville, Hamp- 

 ton and Whitehall and is practically continuous with the Vermont 

 slate district which has much greater economic importance. The 

 slate occurs at several horizons among the metamorphosed Paleo- 

 zoic strata of the region, but belongs mostly to the Cambric and 

 Ordovicic systems. The associated rocks include limestone, shale, 

 sandstone and quartzite. Extensive slate beds are found also in the 

 southern continuation of the metamorphic region along the east side 

 of the Hudson river, in Rensselaer, Columbia and Dutchess coun- 

 ties. Attempts to work the slate in this section, however, have not 

 been permanently successful, though it is recorded that quarries 

 were operated for a time at Hoosick, New Lebanon and Hamburg. 



The slate from Washington county is remarkable for its variety 

 of colors. Red slate is the characteristic product, and has the great- 

 est value owing to its rarity elsewhere. It is quarried chiefly near 

 Granville and in the Hatch Hill and North Granville sections. Pur- 

 ple, mottled and different shades of green slate including the 

 unfading green are also quarried. Nearly all of the product is sold 

 for roofing purposes, as the manufacture of other materials has not 

 been developed to any extent in this State. 



A paper by Henry Leighton, descriptive of the general occurrence 

 of slate in Washington county, and of the practice of quarrying and 

 preparing the material for the market is included in the issue of this 

 report for the year 1909. 



The production of slate increases and decreases irregularly from 

 year to year, though no very great change has taken place in the 

 industry for some time. During the past year the demand for roof- 

 ing material was rather poor owing to the dull conditions in the 

 building trades. The total value of the output as reported by the 

 quarry companies amounted to $83,090 as compared with $127,050 

 in 1909 and $111,217 in 1908. This shows a falling off in the value 

 of nearly 35 per cent. The product of roofing slate amounted to 

 14,107 squares with a value of $79,857, an average value per square 

 of $5.66. In 1909 the roofing slate amounted to 21,187 squares 

 valued at $126,170, an average of $6.99 a square. These averages 

 are above those obtained for the slate in other districts, due to the 

 fact that the red slate commands a very high price, usually from $8 



