rl66 NEW YORK STATE MUSEUM 



East Portchester, Fairfield co. Ct. A small quarry (36) in Har- 

 rison diorite is worked by Antonio D. Parlo & Son near the cor- 

 ner of Henry st. and Bridge st., Port Chester. This quarry is on 

 the Connecticut side of the line but is included here for com- 

 pleteness. The total product is probably less than 500 cubic 

 yards a year, including macadam, rough stone and a small 

 amount of bush-hammered (patent hammered) stone. A granite 

 dike about 10 feet wide cuts the diorite near the opening and 

 material from it is occasionally used by the above firm. 



Greenwich, Fairfield co. Ct. Large quarries (37) in the Harrison 

 diorite are located just south of the New York, New Haven & 

 Hartford railroad tracks, between Port Chester N. Y. and 

 Greenwich Ct. The diorite is here much more massive than in 

 the New York portion of the area and has long been valued as 

 a building stone. The facilities for shipping are excellent, the 

 quarries being almost at the water's edge. The diorite area 

 extends to near Stamford, and small quarries (38) occur at sev- 

 eral points within its boundaries. 



Cortlandt series : gabbro and diorites 

 The dark colored, basic rocks of the Cortlandt series cover an 

 area of about 20 square miles in the towns of Cortlandt and 

 Yorktown, Westchester co. Much of the material is suitable 

 for use as macadam, but unfortunateh' the best material is not 

 near the Hudson river. Much stone has been quarried (39) near 

 Quaker Bridge, Westchester co., for use in the new dam across 

 the Croton river. This rock has been reported on by Prof. J. K. 

 Kemp. An analysis^ made for him by H. T. Yult^, follows: 



Si O2 54.72 



AI2 O3 17.79 



FeaOs 2.08 



FeO 6.03 



Ca O 6.84 



MgO 5.85 



Na2 O 3.02 



K2 3.01 



The specific gravity of the above rock is stated^ as being 2.928. 

 ^Kemp. Handbook of rocks. Ed. 2. 1900. p. 49. 



