100 Geological Survey of the State of New York. 



tion, and is frequently much altered in the vicinity of trap rocks. 

 It affords superior hearth-stones for furnaces, and is employed as 

 a flagging stone, and somewhat for cutting. A red calcareous marl 

 is associated with it, and a gray limestone in beds from one to 

 eight feet thick, affording good building materials and for lime. 



The "red conglomerate limestone" occurs at or near the junc- 

 tion of the red sandstone formation with the primitive rocks, and 

 is composed chiefly of pebbles and angular fragments of gray 

 and black limestone, (like the adjacent primary limestone,) mixed 

 with pebbles of quartz, granite, gneiss, hornblende, sienite, &c., 

 cemented together by a reddish argillo-calcareous paste, mixed 

 with gravel and sand of the same materials. 



The general aspect is like the Potomac marble, and like this would 

 be very desirable for ornamental purposes, except that the hete- 

 rogeneous nature of its ingredients prevents their receiving a uni- 

 form polish. This rock seems to skirt the sandstone on its north 

 edge, and presents us the indicise of the violent agencies that have 

 formerly conflicted, and appears as not an unapt emblem of a 

 fierce border war, in which the weaker party has left on the field 

 the greatest number of slain. 



Dr. Wm. Horton, as assistant, surveyed Orange Co. His obser- 

 vations upon the mineralogy of this region are well known. The 

 while limestone, remarkable for its interesting minerals, is traced 

 in short and broken ledges in granite, from the Hudson near Fort 

 Montgomery, in deposits a few rods in width ; again it occurs 

 interstratified with the granite and hornblende rocks, and a mile 

 wide; and again at intervals, "crosses the Ramapo by the 

 east side of the Dutch Cedar Pond to the New Jersey line," 

 about twenty miles, bearing southwest and northeast. It is 

 coarsely crystalline, forming a handsome calc spar, white and red, 

 and every where contains brucite, black spinelles, pargasite, sah- 

 lite, coccolite, crystallized augite, scapolite, zircon and sphene, 

 serpentine and plumbago. It is often intersected by trap dikes, 

 as at Dutch Cedar Pond, where there are three, one of which is 

 a perfect greenstone, running east and west, and is seen cutting 

 the hmestone perpendicularly for 50 feet. At the inlet of Popelos 

 Pond, the limestone forms a natural bridge, with its arch sustained 

 on one side by hornblende rock, and on the other by granite. (?) 

 More extensive deposits of a similar limestone occur in Warwick, 

 passing near Goshen line into New Jersey, by the drowned lands 



