Ries — Geology of Orange County. 



411 



matter. The fossils found, fixed the age of these rocks as Devonian, probably 

 Hamilton. The plant-remains proved to be Lepidodendron (probably L. 

 ga^pianum) } Calamites, PsilopTiyton and, according to Professor Newberry, 

 Dadoxylon. 



The region was still colored as Potsdam on the geologic map of New 

 Jersey, of 1874, while the area called Hudson river is put down as Silurian 

 slates. In a paper by Dr. T. S. Hunt, the Green pond mountain conglomerate 

 was mapped as greywacke or Upper Taconic (Tram. Roy. Soc. Can., I., ser. 

 IV., page 254). The geologic map of New Jersey, published in the Annual 

 Report of the New Jersey Geological Survey, made no change for the Green 

 Pond-Bearfort region. 



In the New Jersey Geological Survey Report for 1884, Smock gives ;i 

 section from Woodcock hill, northwest of Skunnemunk, southeast and east 

 across Skunnemunk mountain (p. 46), showing the synclinal structure of the 

 mountain. The subsequent work of other geologists shows the main details 

 of this section to be correct. Professor Smock calls attention to the fact that 

 the relations of this Devonian series of rocks are much easier of interpretation 

 in this locality than elsewhere. He also gives a detailed map of the region 

 around Bull hill, northwest of Monroe, and notes the occurrence of plant 

 remains in the Devonian sandstone quarries. 



Dr. Merrill studied this series of rocks in northern New Jersey, and the 

 results of his work are given in the report of the New Jersey Geological 

 Survey, 1886, p. 113. 



In 1892, Professor Prosser gave a resume of previous contributions refer- 

 ring to this region, and discussed in detail the plant-remains of Skunnemunk 

 mountain. N. H. Darton has contributed a valuable paper on the geology of 

 this region (Geologic Relations from Green Pond Mountain, N. J., to 

 Skunnemunk Mountain, N Y.) The results of the writer's work in Orange 

 county during the past summer, agree in most respects with those of Mr. 

 Darton. 



In Bellvale mountain the synclinal is formed, in great part, of the 

 Skunneniunk conglomerate. Excellent exposures of it are seen (184, 186) on 

 the road from Greenwood lake to Warwick, on the summit of the ridge. 

 Interbedded with the conglomerate are less pebbly beds and streaks of red 

 slate. The quartz pebbles are often ground and distorted on slickensides. 4 

 The conglomerate passes through a red quartzite into the flaggy sandstones 

 which are seen lower down on the east side of the mountain. These are 

 everywhere traversed by veins of milk-white quartz (367). 



