14 



prevailing in respect to their composition, between the stratified 

 primary or metamorphic rocks of different belts of country. 



Notwithstanding the innumerable granitic and other veins, 

 •which occur with all the phenomena of violent injection, pene- 

 trating at small intervals every considerable tract of the gneiss 

 rocks of the Highlands, these strata are decidedly less contorted 

 and folded together into those minor flexures so usual among the 

 micaceous beds of this rock forming the southeastern belt. This 

 probably arises from the massive character of its strata, and the 

 absence of the more flexible mineral, the mica. 



The strata are usually highly inclined, their average dip 

 exceeding 45°. In many of the principal mountain ridges an 

 anticlinal arrangement of the dip is plainly visible. In these 

 instances the strata on one flank of the mountain, the north- 

 western, are inclined to the northwest, while on the other they 

 dip to the southeast. 



The common or rather the almost universal direction or strike 

 of the strata, is from the northeast by north to the southwest 

 by south. They are only occasionally found to depart from 

 this direction, which is that of the principal mountain ridges 

 themselves, and indeed of the entire chain of the Highlands, from 

 the Hudson to the Delaware. 



Geographical Extent of the Primary Rocks.' — The general limits 

 of the primary region of the Highlands have already been pointed 

 out in the introductory chapter, when describing the physical 

 aspect of the northern division of the State. The southeastern 

 boundary of this belt was there traced as ranging along the base 

 of the Ramapo, Pompton, Trowbridge, and Mine Mountains; 

 thence along the base of Fox Hill east of German Valley, and 

 the foot of Musconetcong Mountain to the Delaware : the north- 

 western limit was likewise stated to follow the foot of the Pochuck 

 Mountain, Pimple Hill, Furnace Mountain, Jenny Jump Moun- 

 tain, Scott's Mountain, and Marble Mountain, at the Delaware. 

 Between these two somewhat undulating lines are comprised all 

 the primary rocks of New Jersey, if we except the small trian- 

 gular tract of gneiss which enters the State at Trenton, and 

 •which terminates in a point on the Assympink, about six miles 

 east of that town. 

 It has been already mentioned, that all the rocks included between 



