THE MINING AND QUARRY INDUSTRY I912 89 



has caused much unfavorable comment. The tendency to rapid 

 weathering which is announced by a roughening or pitting of the 

 exposed surface seems to be inherent more especially in the mar- 

 bles that have an even grain with the individual particles of square 

 or lounded form. Such particles are not so well interlocked as 

 those of prismatic shape. The weathering in most instances 

 seems to be a mechanical process, simply a loosening of the bond 

 through frost action or the expansion and contraction incident to 

 changes of temperature. Normally, dolomite is harder and more 

 resistent to the attack of solvents than calcium limestones. 



South Dover Marble Co. Of the developed quarries in this 

 section, the principal one in current operation is that of the South 

 Dover Marble Co., situated near Wingdale, Dutchess county, a 

 station on the Harlem Railroad. The area of crystalline lime- 

 stone or marble lies on the flanks of a broad gneiss ridge which 

 extends north and south along the New York-Connecticut bound- 

 ary. The limestone shows a flat or slightly undulating surface in 

 contrast with the rugged contours of the gneiss country. The 

 quarries are about 2 miles in a direct line northeast of Wingdale, 

 but somewhat over that distance by road. They are connected 

 with the mill at the -station by an electric tramway over which the 

 large quarry blocks are transferred for cutting. 



The company operates two quarries, the one being on the east 

 slope of a low ridge facing the gneiss ridge and the second a little 

 farther up the slope and northwest of the former. The lower 

 quarry has an extreme length of 250 feet and a width of 150 feet 

 in the southern half, but considerable less on the north. It is 

 135 feet in extreme depth. There are three derricks in place. The 

 other opening is 150 feet long, 75 feet wide and about 60 feet 

 deep. It has two derricks and an overhead cableway, the latter 

 serving to convey the waste to the dump. 



The marble is of medium texture, with prismatic and angular 

 dolomite particles which measure from .75 to 1 mm. in diameter. 

 It is practically pure white in color, and banding or veining is 

 scarcely noticeable. The structure, as exhibited in the quarry 

 walls, indicates an easterly dip of about 40 for the southern 

 quarry and a westerly one of 5o°-6o° in the northern one, the 

 reversal taking place in the distance of 100 feet. The marble is 

 very compact, though in one place an open joint or water course 

 extends to a depth of 50 feet. It shows slight exfoliation and 

 weathering at the surface, with stained rock to a depth of 10 feet. 



