46 NEW YORK STATE MUSEUM 



The calcareous conglomerate shown in the railroad cut just 

 south of Stonypoint is cut by a fault which trends 80° e, and 

 hades 35° n. The downthrow is probably on the north and ex- 

 ceeds 6 feet. How much more it may be is unknown. 



Northwest border. Faults have been shown to mark a part of 

 the northwestern boundary of the Newark beds in New Jersey. 1 

 Much of the evidence is indirect, but it is is nevertheless convinc- 

 ing. A great fault has determined the boundary from a point 

 near Peapack (N. J.) to a point about a mile west of Stonypoint 

 on the Hudson, a distance of nearly 53 miles. The evidence of 

 the fault is most clearly shown in New Jersey. The boundary 

 line for this interval of 53 miles is remarkably straight. In this 

 respect it is in marked contrast witih those other parts of the 

 boundary both in New Jersey and New York, where the structural 

 relations are such as to demonstrate that no fault exists. The 

 strongest proof of faulting is found in the way the Newark beds 

 terminate against the older rocks. They dip at various angles to 

 the border, more frequently directly toward it than otherwise. 

 In New Jersey the western side of the great Watching mountain 

 syncline has been cut off, so that the shales which outcrop along 

 the border belong to very different stratigraphic horizons. At 

 Bernardsville (N. J.) an outcrop of trap close to the gneiss shows 

 unmistakable evidence of fracturing and shearing. The rock is 

 literally crushed to pieces, so that it is practically a friction 

 breccia. 



In New York the fault has a more easterly trend than the sand- 

 stones and conglomerates have. Consequently, as one goes north- 

 ward, lower strata are constantly found against the older rocks. 

 From Suffern the fault follows the course of Mohawk creek, along 

 the foot of the steep escarpment of Kamapo mountain as far as 

 Ladentown. The gravel terraces of the creek conceal all rock out- 

 crops for several hundred yards from the fault line, so that the 

 actual contact is nowhere seen. At Suffern the conglomerates dip 

 obliquely toward the crystallines. At Orum's quarry and Blau- 

 velt's foundry, several miles northeast of Suffern, the dip is appar- 



lAnnual report of the state geologist of New Jersey for 1897. p. 110-16. 



