104 NEW YORK STATE MUSEUM 



coarser rock under pressure metamorphism. There is evidence of 

 the original coarse grain in occasional fragments of feldspar and 

 quartz which have escaped the general reduction. In its appear- 

 ance and physical characters it resembles the earlier series of 

 Adirondack granites, but does not show their well-defined laminated 

 structure owing to the small proportion of dark minerals. 



The granite was quarried quite actively at one time, and the old 

 quarry face is still conspicuous as a white patch on the face of the 

 ridge. The quarry property is owned by Henry McGurk of Sara- 

 toga Springs by whom it was last worked about twenty years ago. 

 It was operated mainly for paving blocks which were used in the 

 streets of Albany and Brooklyn, but some building material was 

 sold of which a specimen structure may be seen in the Hathorn 

 vault in Saratoga Springs. 



The quarry face lies about 80 feet above the base of the ridge 

 and is 100 feet long. The stone has been quarried back for 60 feet 

 or more. Apparently the granite was shot down in large masses 

 which were then broken up and trimmed into paving blocks on the 

 spot. A large amount of waste had accumulated on the quarry 

 floor to the obstruction of the progress of development. The rock 

 is traversed by two series of joints of which the more prominent 

 has a course about N. 25 E. dipping 8o° northwest, and the other 

 about N. 6o° W. with a dip of 8o° northeast. There is also a series 

 of division planes inclining about 40 to the south, parallel to which 

 a faint lamination can be seen in the granite owing to parallel 

 orientation of the biotite scales. It is said to have a good rift and 

 grain so as to dress readily with even surfaces. Small bands of 

 lighter granite are intercalated parallel with the lamination in parts 

 of the quarry, and occasional knots or segregations of pegmatite and 

 vein quartz are observable. There is, however, a good proportion 

 of uniform material that could be used for building stone. 



The granite is medium gray with very little of the dark silicates, 

 which are limited mainly to biotite. Garnet in the form of grains 

 and aggregates of grains up to an inch across is a subordinate but 

 rather conspicuous constituent. The texture is compact, and the 

 particles of quartz and feldspars average between 1 and 2 mm in 

 diameter, the rock thus belonging to the fine-grained granites. 



Microscopic examination. The feldspar consists of orthoclase, 

 microcline and oligoclase, all of which show some alteration: to 

 sericite which impairs the quality of hardness. The particles are 

 broken and angular and show strain shadows, evidencing the in- 

 tense compression the rock has undergone. The quartz fills in the 



