Il6 NEW YORK STATE MUSEUM 



and the other inclined 8o° or 90° and striking N. 30 W. The rift 

 is about north-south and nearly vertical. The joints are irregularly 

 spaced, usually at fairly wide intervals, but in one place form a 

 heading where only material for crushing purposes is secured. 

 Dimension stone of almost any merchantable size can be quarried. 



Knots and streaks are rare and dikes apparently absent. There 

 are occasional inclusions of the country schists, the larger ones 

 being on the northwest and east sides of the quarries. A con- 

 spicuous example which is found on the north side of the incline 

 consists of black hornblende schist that has been injected by granite 

 and pegmatite and forms a vertical wall for a short distance, wedg- 

 ing out finally in the granite which apparently surrounds it com- 

 pletely. 



The quarries are equipped with modern machinery for breaking, 

 hoisting and cutting the granite, but as yet are scarcely developed 

 to the stage that admits the most advantageous operations. The 

 stone is mostly dressed on the ground. The cost of haulage by 

 wagon to Peekskill makes that necessary. Increased facilities for 

 cutting have recently been provided by the erection of a steel-frame 

 shed of dimensions 130 by 50 feet. The capacity for turning out 

 finished material is thereby more than doubled. The equipment at 

 the quarries includes a 50-ton crushing plant for working up the 

 waste material. 



Microscopic character. The granite from this locality belongs 

 to the medium-grained class, inclining toward the finer end of the 

 scale. It is a mixture of feldspar, quartz and mica in their order 

 of abundance. The feldspar and quartz are mostly under .25 cm 

 in diameter, the quartz individuals occasionally slightly exceeding 

 that limit. The mica includes both biotite and muscovite and is so 

 finely divided and evenly distributed as to be little noticeable except 

 against the white background of the light gray granite. The feld- 

 spars include albite, oligoclase and subordinate orthoclase, all of 

 which show incipient alteration by their clouded appearance under 

 the microscope. Chlorite is sparingly present as an alteration 

 product of the biotite. The accessory constituents include magnetite, 

 zircon and apatite in very small amounts. 



The yellow or golden hue characteristic of the superficial part of 

 the granite is due to the presence of a little limonite stain distributed 

 along the borders and microscopic cracks of the quartz and feldspar, 

 particularly of the quartz which seems to carry most of the color- 

 ing matter. The stain is not accompanied by any marked softening 

 or decomposition, contrary to what might perhaps be expected, for 



