114 NEW YORK STATE MUSEUM 



ments still remain in a down- faulted remnant just to the west, form- 

 ing Schunnemunk mountain. It is not reasonable to assume that 

 such a great series stopped at this line. Indeed sediments of this 

 type occur as down-faulted blocks in the Highlands, much farther 

 to the southwest in New Jersey, but in this particular area no rem- 

 nants are found inside the Highlands belt. That they once entirely 

 covered the area may be assumed, and if they did, it simplifies very 

 much the understanding of the behavior of some of the formations 

 which show metamorphism and deformation inconsistent wath any 

 condition except development under considerable load. 



Appalachian deformation. Mountain folding with much thrust 

 faulting, is recorded abundantly in territory adjacent to this quad- 

 rangle in rocks of later age than the Taconic deformation. In this 

 quadrangle, however, no later Palaeozoic rocks are preserved, so that 

 the check on the time of the deformation epochs is inadequate. 



Considering the quality of the later deformation, however, with 

 its tendency to thrust faulting and the ])rominence of folding, it 

 seems certain that some of the deformation of this area is of the 

 same age as the Appalachian revolution. It is particularly difficult, 

 however, to discriminate with certainty between this and the previous 

 epoch. The tendency is to charge most of these features to the 

 Appalachian deformation, and this is probably correct. The big 

 thrust, for example, along the north margin of the Highlands on 

 the northwest side of Storm King mountain and Breakneck ridge is 

 a type of deformation that one would expect in connection with the 

 Appalachian folding and faulting. The close crowding of the now 

 down-faulted block, lying in I^eekskill Hollow, is another that prob- 

 ably belongs to this period, and there are doubtless many others, 

 especially those marking the strong northeast-southwest lines of 

 weaknesses. What appears in these rocks as cru.sh zones and longi- 

 tudinal weaknesses may have appeared at the surface of that time as 

 faults and folds. 



It is probably not necessary to attempt a closer discrimination 

 than this. It is certain that the Appalachian deformation is strongly 

 represented and it is probable also that the chief weaknesses of the 

 Highlands are connected with that dynamic event. 



Post-Paleozoic time. No Mesozoic rocks are found in this 

 quadrangle, but they are extensively represented in the quadrangle 

 immediately adjacent on the southwest. The West Point quadrangle 

 almost touches the northeastward extension of the great Triassic 

 block of north-central New Jersey. It is entirely likely also that 



I 



