454 



Report of the State Geologist. 



About one-quarter of a mile beyond Mr. Harriman's house, the gneiss 

 becomes very quartzose and shows many crumples and slickensides. It is a 

 mixture of plagioclase, biotite, and pyroxene. The two latter occur as parallel 

 growths and the same cracks traverse both minerals. Another specimen of the 

 same gneiss from farther up the road (281), shows, in sections, a similar 

 character but the pyroxene is often nearly colorless and much corroded, while 

 magnetite is present in small amounts. The strike is N. 40° E., the dip 

 45° ~N. E. The gneiss once again becomes dark-colored, very massive, and 

 hornblendic and is cut by an east and west dike about one foot wide. The 

 rock on either side of the dike is broken by many joints running parallel to 

 the dike, and the gneiss strikes N. and S. with a dip of 60° E. The gneiss 

 again passes into the normal form along the road above the waterfall. It 

 a\ ill be thus seen that there are alternations of the normal gneiss and the 

 hornblendic form. 



At Mr. Cunningham's house, about a mile and one-half up the road from 

 Mr. Harriman's, the road branches off to the east. Just behind Mr. Cunning- 

 ham's, the gneiss contains a small bed of iron-ore. A small pit was 

 sunk in it to a depth of nearly forty feet and a little ore taken out, but 

 most of it was very lean. Across the road to the north a small dike cuts 

 the gneiss. 



About a mile farther east, are several more small iron mines south of the 

 mad. They are the Greenwood, Hogencamp, and Tompkins mines. The 

 wall-rock of each is a hornblendic gneiss with some granular pyroxene* 

 The largest mines in this region are the Bradley mines, one and one-half miles 

 north-east of Cunningham's house, and on the road to Queensboro. Judging 

 from the size of the opening, a large amount of ore has been taken out. The 

 ore crops out above the road and a cut was made to intersect it at a lower 

 level. The bed of magnetite dips to the north and is fully forty feet thick. 

 Associated w ith the ore are great quantities of calcite containing crystals of 

 magnetite, apatite, pyroxene, titanite, amphibole, and grains of pyrite. Two 

 dikes also cut the ore-body, one a porphyritic camptonite, the other a fine- 

 grained quartz porphyry. This latter is a new* one to the Highland region of 

 Orange county. They are both hereafter described in further detail. 



From Cunningham's house to Two Ponds, the road leads through the 

 woods and there are few outcrops. Where these are found, the rock is 

 generally a massive gneiss dipping to the east and striking from X. 20° E. to 

 X. 40° E. At a point w here the road sw ings around to the w est, just before 

 passing between Two Ponds, the gneiss is cut by a dike which may be an 



