REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 rl65 



The granite quarried by the Pochuck granite co. was tested^ 

 by Prof. J. P. Carlin, with the following results. 



Compression tests of granite 





Size of cube in inches 



Area 



First crack at 



Ultimate strength 





Total 



per 

 sq. inch 



1 



2 



2.02 by 1.98 by 2 



2 bv2.1 bv 2 



4 sq. in. 

 4.2 sq. in. 



66 500 lb 

 74 000 lb 



94 000 

 96 000 



23 500 

 22 900 









Harrison diorite 



The Harrison diorite is a medium grained granite diorite^ 

 containing typically quartz, plagioclase (with subordinate ortho- 

 clase and microcline) and biotite. In Westchester county it 

 covers a large part of the towns of Mamaroneck, Rye and Har- 

 rison, and the same area extends eastward into Fairfield county, 

 Ot. as far as Stanaford. In the New York portion of the area 

 it is intrusive in the Hudson schist. 



In that part of the Harrison diorite area which falls in West- 

 chester county the diorite is generally highly foliated and often 

 somewhat disintegrated on the outcrop. It is only quarried at 

 one point in the area, which is described below. Several Con- 

 necticut quarries are also noted. 



Larchmont, Westchester co. Campbell's quarry (35) is owned 

 and operated by W. H. Campbell of Larchmont. All the product 

 so far has been used on buildings erected by Mr Campbell. The 

 quarry has been worked for about four years, and the total out- 

 put is estimated at 4000 cubic yards. This is all used as dressed 

 stone (bush hammered). The stone is of good quality. It is 

 not much foliated, and has a rather pleasant bluish color. It 

 is said to stand dressing well. In addition to the quartz and 

 plagioclase, however, it contains much biotite and numerous 

 garnets about ^ inch in diameter. Sheared orthoclase is very 

 infrequent. In a slide the feldspars are seen to be somewhat 

 clouded but the biotite is very fresh. 



^U. S. geol. sur. 20th an. rep't. Pt 6, continued, p. 421. 



