rl52 NEW YORK STATE MUSEUM 



highly foliated, and consisting chiefly of quartz, plagioclase (witb 

 subordinate orthoclase) and hornblende. The feldspars are usu- 

 ally white, varying to reddish; and the gneiss is accordingly 

 gray to light reddish in color. Part of the stone is used, rough 

 dressed, for foundation and wall work; but a considerable quan- 

 tity is cut by Copeland & Son at Suffern, being used chiefly for 

 monuments. 



Arden, Orange co. Several quarries (7) between Arden and 

 Tuxedo Park have been worked quite extensively for road metal. 

 The material is a hornblendic pre-Cambrian gneiss, not suitable- 

 for dressed stone, but as road metal producers the quarries are 

 of some local importance. 



Monroe, Orange co. A pinkish gneiss occurs in an area of con- 

 siderable size about 2^ miles southeast of Monroe, Orange co. 

 It has never been worked, but judging from the outcrop should 

 furnish stone of good quality. So far as color is concerned, it 

 is probably the handsomest granite in southeastern New York. 



Fordham gneiss 

 The Fordham gneiss is typically a light grayish or bluish,, 

 well banded gneiss, consisting of biotite, orthoclase and quartz. 

 Its upperi beds near the contact with the Poughquag quartzite 

 are always highly quartzose; and this upper part of the 

 formation is possibly of sedimentary origin. The Fordham 

 gneiss has been largely used for foundation stone and other 

 uncut work. The Hastings quarry formerly sold a fair propor- 

 tion of its product as cut stone, but of late years little of this 

 grade has been marketed. It has also been used to some extent 

 for macadam, but is hardly well fitted for this purpose as it 

 generally breaks into flat pieces when put through a crusher. 



^ " Upper " is used here in a geologic sense. Folding of the rock series 

 may cause the ncTrer (and geologically " upper ") beds to apparently 

 underlie the older (and geologically " lower ") beds. This is well shown 

 at the old marble quarry near Hastings, Westchester county. The series 

 here has been sharply folded so that the limestones are shown dipping 

 to the east, apparently under the quartzite and gneiss which are exposed 

 near the top of the eastern wall of the quarry; but the limestone is really 

 newer than the gneiss and quartzite. 



