12 



GEOLOGY. 



to the tilting and incipient folding, the series is extensively faulted, 

 and that in a somewhat complicated manner. Some of the faults are 

 strike faults (parallel to the strike), some dip faults (right angles to 

 the strike), while others are oblique in various degrees. There is 

 also a fault or a series of faults along the eastern margin of the series. 

 The faults, affecting as they do a series of variable hardness (the trap 

 being much harder than the clastic beds), have determined many of 

 the peculiar topographic features of the Connecticut River basin, 

 and some of the details of its outlines. The faulting has also given 



Fig. 315. — Contact of intrusive rock with sedimentary. Palisade Ridge, N. J. 



rise to very notable peculiarities of outcrop. This is best illustrated 

 by the outcrops of the trap sheets (Figs. 318, 319, and 321). 



In the New York- Virginia area the structure is likewise mono- 

 clinal, but the general direction of dip is to the northwest (10°- 15°). 

 This contrast of dips between the New England and New Jersey areas 

 was thought to give color to the hypothesis that the strata of the two 

 areas are parts of one huge anticline from the broad crest of which 

 the beds have been removed. As in New England, the beds of the 

 New York-Virginia area are never closely folded, though several broad 

 anticlines and synclines have been shown to exist. The series of this 

 area is also extensively faulted, the total number of faults known in 



