3S4 DARTON — aREEN" POND, N. J., TO SKUNNEMUNK MT., N. Y. 



Copperas mountain, and the surface is a relatively level one. Small en- 

 closed areas of the crystallines are bared by erosion of the conglomerate 

 along the two anticlinals south of Newfoundland, and I find that gneiss 

 extends to within half a mile of the depot in the western flexure. Along 

 the axis of the eastern flexure, gneiss extends to and under Green pond 

 and down the gorge of the outlet of the pond to the end of Copperas 

 mountain. Along these anticlinals no actual contacts were found, but 

 from many exposures in its vicinity the relative evenness of the floor 

 was clearly apparent. In the Bowling Green mountain the conglomerate 

 is wrapped around the northern end of a ridge of gneiss, but its contact 

 relations were not observed. 



The conglomerate becomes finer grained in its upper j^art and rapidly 

 merges into the quartzites. These are moderately thick-bedded, very 

 hard, fine-grained members, which vary in thickness from 250 feet about 

 Newfoundland to 5 or 6 feet near Cornwall station. They are usually 

 reddish or buff in color, but brown and light gra}^ tints are often seen. 

 The crest and western slopes of Green Pond, Kanouse and Copperas 

 mountains and the northern slope of Bowling Green mountain consist 

 of this rock. It is again exposed on the western shore of the southern 

 end of Greenwood lake, along the crest of Pine hill, northeast of Monroe, 

 and just west of the crest of the ridge at Cornwall Station. At New- 

 foundland it is well exposed a few yards west of the station, dipping 

 around the declining end of the anticlinal. 



The quartzites grade upward into the Longwood red shales, and the 

 intergrading is exposed at a number of jDoints along the west slope of 

 Green Pond mountain and in New York. On the northwestern slope of 

 Pine hill, beds of passage are finely exposed, and the red shale and red 

 quartzite are interlaminated for a thickness of several feet. 



The age of the Green Pond conglomerate and quartzite is aj)proxi- 

 mately the same as the Shawangunk grit and Oneida conglomerate, and 

 probably they also represent all or a portion of the Medina. They are, 

 at any rate, the representatives of the great arenaceous sedimentation at 

 the beginning of the Upper Silurian. The evidence of their position is 

 mainly their intimate relation to the Helderberg limestone throughout 

 and the fact that they overlie the Hudson shales in New York and prob- 

 ably also in New Jersey. Throughout their course in New Jersey and 

 New York the upper quartzites grade into the LongAVOod red shales, and 

 these into the Helderberg limestone, constituting a series which overlaps 

 the Archean, the Cambrian limestone and the Hudson shales. This strati- 

 graphic relation, as well as precise lithologic similarity, served to corre- 

 late the Pine hill and Cornwall station areas with those of the Green 

 pond region in New Jersey. The superposition on the Hudson shale is 



