17 



with the older secondary limestone, as far as a point about two 

 miles south of Flanders. From hence, along the same side of 

 the same topographical valley, it is marked by the overlapping 

 diluvial matter of the Succasunny Plains. Beyond the ter- 

 mination of these plains, northeast of the village of Succasunny, 

 the primary rocks, pursuing still the southeastern edge of the 

 same valley prolonged, come in contact with the middle secondary 

 strata of the Green Pond and Copperas Mountain, as far as the 

 Pequannock. Northeast of this stream, for a range of several 

 miles, they disappear beneath the older secondary limestone of 

 the Macapin Pond. Beyond this limestone to the State line, 

 they come again in contact with ihe red sandstone beds of the 

 Copperas Mountain, here called the Long Pond Mountain. This 

 part of the boundary is marked by the southeastern side of the 

 valley of Belcher's creek, nearly to Long Pond. 



Another axis or elevated belt of the primary rocks, still more 

 extensive than that just described, as respects length, lies imme- 

 diately to its northwest, separated only by the long line of valley 

 already traced. The southeastern margin of this latter tract of 

 the gneiss coincides from the State line to the Pequannock, in 

 some places with the red sandstone strata of the Long Pond Moun- 

 tain, and in some places with the slate and limestone formations 

 of the older secondary group, while in other neighbourhoods, it 

 is separated from these by a narrow strip of diluvium, forming 

 the bed of the intervening valley. From th.e Pequannock south- 

 ward to Flanders, it ranges at an average distance of half a mile 

 from the northwestern base of the Green Pond Mountain, its imme- 

 diate boundary being the diluvium of the Longwood and Berk- 

 shire Valley and their prolongation. 



Thus covered, the edge of the gneiss passes Drakeville and 

 Flanders, until, beyond the latter place, it encounters the older 

 secondary limestone of German Valley. It thence extends down 

 along the northwestern side of this valley to its outlet north of 

 Clinton, the limestone every where forming the overlapping stra- 

 tum. From the neighbourhood of Clinton, its course is first nearly 

 westward to the vicinity of Vansickle's, and thence southwestward, 

 following the base of the Musconetcong Mountain to the Dela- 

 ware. Between the South Branch, north of Clinton and the head 

 of Milford creek, the gneiss rocks dip beneath the ancient lime- 



2* 



