QUARRY MATERIALS OF NEW YORK . 1 53 



about 2 miles in maximum diameter from northeast to southwest 

 and is about i mile wide. It is thus sufficiently large to permit the 

 location of many quarries within its bounds, although as yet un- 

 developed. The rock is very fine-grained and is somewhat vesicular 

 in places ; it may be a surface development of the Palisades diabase. 



SUFFERN, ROCKLAND COUNTY 



Union Hill, near Suflern, consists of a mass of trap from one- 

 fourth to one-half of a mile in diameter. The rock is a fine-grained, 

 compact diabase of the same composition as the Palisades rock. 

 The Ramapo Trap Rock Co. has opened quarries in the exposure 

 for the production of crushed stone. • 



PORT RICHMOND, RICHMOND COUNTY 



The southern end of the Palisades diabase is found on Staten 

 Island where the intrusion forms a low ridge that extends south- 

 southwest from Port Richmond. The exact limits of the area are 

 not well marked, but it probably is from one-fourth to one-half of 

 a mile wide and terminates somewhere near Linoleumville. Quar- 

 ries have been opened at Graniteville and Port Richmond. For the 

 last few years they have been inactive. 



