Ries — Geology of Orange County. 



41. 'J 



Cambrian. The Cambrian limestone underlies the drift-filled valley 

 northeast of Greenwood lake, as far north as Long pond. There are small 

 outcrops of it along the base of Bell vale mountain (434), west of Moses 

 Smith's house, and also in a ravine to the northeast (423). The gneiss 

 crops out about 200 feet from it, up the hill-side. The rock is light bluish 

 grey, cherty and massive, and contains numerous slit-like cavities. Scattered 

 Over the surface at this locality are many angular fragments of Oriskany 

 quartzite and conglomerate, which appear not to have been transported 

 any great distance. The limestone probably rests unconformably on the 

 gneiss of the eastern side of the valley. 



To the northwest of Bell vale mountain, the Cambrian limestone, which 

 spreads out over the Warwick valley, as previously noted, rests uncon- 

 formably on the gneiss. A good outcrop of this limestone is in the corner 

 of a field just northwest of Bellvale (107). It shows a thin-bedded character, 

 and has shaly layers. The strike is N. 50° E., and the dip 30 u W. Mr. 

 Darton* notes a very small outcrop of Helderberg limestone on the northwest 

 slope of Bellvale mountain, and about one-half mile north of the road across 

 the mountain. The rock is said to be a dark grey, moderately pure limestone. 

 Only one shell was found in it, and that resembled St/rophonella punctidiftra, 

 Conrad. 



Pre-Cambrian Gneiss. The gneiss, which is faulted up against the 

 Devonian rocks on the northwest side of Bellvale mountain, enters the 

 county as a belt four miles wide, and narrows rapidly towards Bellvale, 

 whence it extends northward, as a narrow strip, to Sugar Loaf. It has a 

 steep dip. Near the fault line, the gneiss is massive and hornblendic 

 (188, 364, 365). The strike east of Bellvale (188) is N. 30 to 35° E. ; 

 dip, 80° S. E., and north of Bellvale (188) the strike is N. 25" E. ; dip, 

 30° S. E. At times the hornblende predominates to such an extent as to 

 make the rock black. Toward the west the basic gneiss is succeeded by a 

 more acid phase, containing much orthoclase and mica. 



The gneiss retains the acid character over most of the area south of 

 Warwick and Bellvale. About two and one-half miles due south of Warwick, 

 several openings have been made for iron-ore in the hornblendic gneiss. 

 North of the latitude of Lawton, the gneiss area broadens again to form Sugar 

 Loaf and Goose pond mountains. The gneiss forming these hills is a 

 moderately fine-grained mixture of quartz and feldspar with little or no mica 

 and rarely hornblende. The dip is prevailingly steep to the east. Graphite 



* Bulletin Geological Society of America, V., p. 380. 



