4 24 



Report ok the State Geologist. 



distance up the flanks of the hills. The road swings around to the north and 

 intersects another, which turns east along the north side of Round hill. 

 This road traverses the hill until it rises steeply about three-quarters of a mile 

 west of the cross-roads. At this point (241), the gneiss is again met, cropping 

 out along the roadside. It is very massive, and farther up the hill becomes 

 very hornblendic. The rock is deeply stained with iron. The strike here 

 is N. 40° E., and the dip 70° S. E. An opening for magnetite has been 

 made at the summit of the hill. The slate appears with a western dip 

 within twenty feet of the gneiss, and evidently rests on it unconformably. 

 It shows numerous local crumplings, The gneiss extends along the south 

 side of the road, as far as the school-house at the cross-roads; while the 

 slate forms the slope to the north of the road. Toward the school-house 

 the gneiss becomes more granitic and coarse-grained. Layers of graphitic 

 schist and pegmatite veins are very numerous at this point. Woodcock hill 

 to the northeast is quartzose gneiss, with much graphite in the exposures 

 at the north end of the hill. The strike at the north end is N. 80" E., 

 the dip 70° E. The constant eastern dip in this range of gneiss hills is 

 noticeable. A spur of the gneiss crosses the road to the east, and is seen in 

 the woods within a few feet of the limestone (340). To the north the gneiss 

 disappears under the slate. 



Geology of the Reg-ion East and Southeast of Skunnemunk Mountain. 



The Cambrian limestones which are seen in the valley north of Green- 

 wood lake are covered by drift as far as the valley of the Ramapo, 

 cast of Monroe, The limestone extends from a point about two miles 

 south of Monroe, eastward to Turners, and a short distance beyond that point 

 in a southeasterly direction. The most western exposure is in the road-bed 

 a few hundred feet east of the Clove mine, and near a large barn. At this 

 point it is thick-bedded and intersected by numerous joints. A little, farther 

 to the east at the cross-road (220), the limestone is argillaceous and shaly, 

 with a barely perceptible dip to the northwest. The outcrops show a similar 

 shaly character at the other end of this cross-road (445) with a low northeast 

 dip. In the limestone quarry to the north, the rock is massively bedded and 

 hard. The limestone here is light bluish grey, in layers six inches to two 

 feet thick, and fine-grained. It has a low dip of twenty degrees to the north- 

 wot. The rock is much weathered along the numerous vertical joints, and 

 contains many small cavities lined with crystals of quartz and calcite. About 

 twenty-live feet are exposed. 



