GREEN POXD CONGLOMERATE. 383 



formation extends along the western sloj^e of Green Pond mountain, 

 and around the northern end of BowHng Green mountain, where it is 

 frequently exposed. The thickness in New Jersey is estimated at 200 

 feet by Merrill, but its average amount does not appear to be more than 

 150 feet. 



The Longwood red shales are similar in general appearance to some of 

 the shales associated with the Skunnemunk conHomerate in Bearfort 

 mountain, but, as noted by Merrill, the stratigraphic relations are entirely 

 different. Where they are associated with quartzites in New Jersey they 

 are underlain by them. 



Green Fond Conglomerate. — The greatest development of this formation 

 is in New Jersey, where it is continuous over a wide area, and gives rise 

 to a number of prominent ridges. In New York there are three small 

 outlying areas : Pine hill, northeast of Monroe, and two small ridges 

 west of Cornwall station. Throughout its course it consists of coarse, red 

 conglomerates below and buff and reddish quartzites above, and the char- 

 acteristics of these members are uniform throughout. The conglomerates 

 consist of quartz pebbles from one-half inch to two inches in diameter 

 in greater part, in a hard, sandy, quartzitic matrix of dull red color. 

 The proportion of pebbles to matrix is usually large, but there is local 

 variation in this regard. The pebbles are mainly well rounded, but 

 some subangular ones occur. They are almost all of quartz, and white 

 or pinkish in color. No quartzite pebbles were observed. In this char- 

 acteristic the Green Pond conglomerate differs greatly from the Skun- 

 nemunk conglomerate, but otherwise they are very similar. The thick- 

 ness of the Green Pond conglomerate varies. In New York there are 

 not over 60 feet, but in New Jersey it will probably be found to average 

 about 150 feet in its greatest development in Green Pond and Copperas 

 mountains. Owing to its extreme hardness and massiveness, it gives 

 rise to high, rocky ridges with precipitous slopes in greater part. Green 

 Pond, Copperas, Kanouse and Bowling Green mountains are the most 

 prominent of these, and they occupy an area of considerable size in 

 New Jersey. South of the south end of Green Pond mountain west of 

 Dover there are outliers of conglomerates and sandstones probably of 

 this age, of which the distribution is indistincth^ shown in figure 1. 

 They are descril)ed by Cook in the " Geology of New Jersey," 1868. 



In the vicinity of Cornwall Station the conglomerate lies on Hudson 

 shales ; in Pine hill, on Cambrian limestone, at least in part ; in Kanouse 

 mountain, on slates possibly of Hudson age, northward, and on Cambrian 

 limestone southward; in Green Pond, Copperas and Bowling Green 

 mountains it lies directly on the crystalline rocks. The contact with the 

 crystalline rocks is exposed along the upper part of the eastern slopes of 



LIV— Bui-i. Geoi, Soc. Am., Vol. 5. 1893. 



