QUARRY MATERIALS OF NEW YORK 139 



of the Wallkill river. Both are made up of a coarse hornblende 

 granite, somewhat gneissoid in places and showing pegmatitic and 

 aplitic variations. Mount Eve, the larger boss, occupies an area 

 about 2 miles long and a mile wide. Mount Adam is a nearly round 

 mass, about one-half of a mile in diameter. There are small knobs 

 of the same granite near Big island, just northeast of Mount Eve 

 and also in the section southwest, along the general axis of the 

 main intrusion. 



Pochuck mountain, a broad ridge which lies principally in New 

 Jersey, consists of Precambric gneiss broken here and there by 

 granite. On the northeastern end, the part within New York 

 State, the easterly slopes are formed by a coarse, quite massive, 

 hornblende granite, but the western half is made up of biotite 

 gneiss. The granite is lighter in color than that just mentioned 

 but its mineral composition is similar and it may be of related 

 origin. 



The section of the Highlands in the vicinity of these intrusions 

 possesses much interest to the geologist. The contact zones between 

 the granites and the bordering limestones are especially notable and 

 have long been a favorite collecting ground from which much ma- 

 terial has found its way into museums. The geological features 

 of this section are set forth in numerous papers and reports, the 

 more recent being those by Kemp and Hollick x and by Ries. 2 



Quarries on Mount Adam and Mount Eve 



Practically the same kind of granite is exposed on the two knobs, 

 Mount Adam and Mount Eve, and they belong no doubt to a single 

 intrusion, though separated by a belt of crystalline limestone. 

 Mount Eve, the larger knob, rises to an altitude of 1057 feet above 

 sea level; its greatest axis in the direction northeast-southwest is 

 about 2 miles. Mount Adam, which is really a spur on its western 

 flank, measures little more than one-half of a mile in diameter, 

 with a summit about 100 feet below that of Mount Eve. Smaller 

 knobs of the granite are found at Big island, just north of Mount 

 Eve and on the eastern and southern borders of the mountain. 



The granite resembles that from Pochuck mountain in general 

 character and composition. It belongs to the hornblende granites, 



1 The Granite at Mounts Adam and Eve and Its Contact Phenomena, 

 N. Y. Acad. Sci. Annals VII, 638. 



2 Report on the Geology of Orange County, N. Y. State Museum Rep't 49, 

 2, 1895. 



