REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 llGl 



torted to be used for anything save backing and probably not 

 over 500 cubic yards were used even for that. It is cut by three 

 sets of joints — two approximately vertical, and one horizontal. 

 They strike and dip respectively n. 37° e., 85° w.; n. 73° w., 

 80° e.; and n. 23° e., 20° w. 'Fragments of vein quartz, with 

 faceted surfaces, were found on the dump, and several specimens 

 of chalcopyrite were seen. Pegmatitic material also occurs. 

 Much of the rock is highly micaceous and thin bedded, while the 

 more solid portions are too much distorted to be used for face 

 stones. The quarry will probably never be reopened. 



Tarrytown, Westchester co. The old Beekman quarry (23a), on 

 land belonging to the Kingsland estate, is located about 1 mile 

 north of Tarrj-town, near the Hudson river. It was formerly 

 largely worked both for structural stone and, later, for railroad 

 ballast. The material is a bluish to reddish gneiss similar in 

 mineral composition to the Yonkers gneiss. Examples of it can 

 be seen in several churches and other large buildings in Tarry- 

 town. Gillmore reports a gneiss from Tarrytown, probably 

 from this quarry, as showing in 2 inch cubes a compressive 

 strength of 18,250 pounds a square inch, and as having a specific 

 gravity of 2.655. 



Ravenswood, Queens co. The eruptive area in Ravenswood L. I. 

 (25), is composed of rock allied to the Yonkers gneiss but con- 

 taining plagioclase in addition to the sheared orthoclase of the 

 normal Yonkers. The occurrence of perthite in pegmatitic 

 bands is noteworthy. It has been used to some extent in founda- 

 tions, walls, and even buildings in the vicinity, according to my 

 observations. Most of the area, however, falls within the limits 

 of a public park. 



Granites and allied rocks in small areas 

 At many points in the area under consideration the members 

 of the normal succession are cut by dikes and bosses of granites 

 and granite-diorites. Coarse grained (pegmatitic) intrusives 

 are of very frequent occurrence, particularly on and near Man- 

 hattan island, where such dikes are frequently shown cutting 

 the Hudson schists. These materials are, of course, of no eco- 



