48 



northeastern margin, by a succession of long and narrow syn- 

 clinal belts, consisting of the slate of the overlying formation. 



The general southeastern border of this large limestone district 

 has been already traced in sufficient detail, when describing in 

 another chapter, the northwestern limit of the main continuous 

 range of the primary, above referred to. It was stated as keep- 

 ing a little to the southeast of the Musconetcong creek from its 

 mouth nearly to Stanhope, towards its source, and thence to 

 extend in a more wavering line along the base of the Wallkill 

 Mountain to New York. 



Its northwestern margin, separating it from the main continuous 

 slate belt of the Kittatinny Valley, may be given as extending 

 longitudinally in a somewhat undulating course, through the middle 

 of that valley, from a little above Belvidere, on the Delaware, to 

 near the intersection of the Wallkill and the state line of New 

 York. 



Tracing this boundary more minutely, it will be found, begin- 

 ning at the Delaware, to run in a northeast direction for about 

 four miles, to the little village of Sarepta, to deflect thence north 

 for several miles, to the Free Church, on the road from Hope to 

 Columbia ; passing which, it sweeps again towards the east, until 

 it reaches the vicinity of Johnsonburg. From this point to the 

 New York line, it preserves a nearly straight course, skirting 

 the town of Newton on the northwest, passing a little west of the 

 villacre of Harmonyvale and a corresponding distance east of 

 Deckertown, and meeting the meadows of the Wallkill about 

 three miles to the southwest of the line bounding the State. 



The large zone of limestone now delineated, offers many curi- 

 ous features to the geologist. Conspicuous among these are its 

 numerous anticlinal axes and the striking phenomena of an in- 

 duced crystallization, elTected along certain belts of the stratum 

 by the heating agency of the numerous igneous dikes and veins 

 which traverse it. These will be systematically described and 

 traced in their own more appropriate places. In the mean while, 

 we proceed to give the boundaries of the other lesser bands of 

 the limestone formation. 



Next in extent of surface to the broad area already traced, is 

 the smaller parallel tract of the valley of the Faulinskill, lying to 

 the northwest. Commencing at Coursinville in a wedge-shaped 



