ELIZABETHTOWN AND PORT HENRY QUADRANGLES 9I 



of Westport. The small block of Potsdam sandstone at the south 

 end of the area is tilted in northeastern direction. 



The presence of outcrops of Beekmantown beds west of the 

 Chazy, Black River and Trenton belts of this area, directly in the 

 strike of the latter [see below] necessitates the assumption of a 

 branch fault of the master fault striking toward northeast. This 

 fault is quite likely to come out under and be a factor in the forma- 

 tion of the drift-filled shore between Westport and Cold Spring bay. 



The Port Henry block is mainly tilted to the east and northeast; 

 but clearly much broken by smaller faults. Along the railroad and 

 near the shore the beds lie rather flat, near the western fault scarp 

 they dip, however, steeply to the east and near the southern 

 boundary they dip equally strongly south, but close to the fault 

 scarp (as in the railroad cut south of Port Henry) they dip strongly 

 north. The strong easterly dip along the western boundary and the 

 north dip along the south boundary are obviously both due to 

 dragging. These dips hence support the conclusion of the presence 

 of the faults that intersect at nearly right angles near the Y of 

 the Mineville Railroad, forming there the highest point of the tilted 

 fault block. 



That also the Beekmantown beds at the north end of the area 

 which seem to rest in regular succession on the Potsdam beds are 

 much fractured is well seen in the railroad cut where especially 

 the black chert bands bring out distinct fault lines with the down- 

 throw to the north and a throw of but a few feet. A larger fault 

 appears to separate the divisions A and B of the Beekmantown. 

 This is indicated by a depression between them and the different 

 dips. With these numerous orogenic disturbances is quite clearly 

 connected also the brecciated condition of much of the Beekman- 

 town dolomite. The chert bands of the railroad cut furnish here 

 again instructive examples. They are seen to be bent very irregu- 

 larly and broken into angular fragments in other places, at one 

 point the contorted band having doubled around the fragments. It 

 is to be inferred that the brecciated beds slipped when still under 

 the enormous weight of the overlying younger Paleozoic rocks and, 

 were faulted, and thus a crush breccia formed. 



The Crown Point area is in its entire structure a part of the 

 Vermont plain, as already recognized by Hitchcock, Brainerd and 

 Seely and indicated by the continuity of the strikes across the 

 lake at Chimney point. The northeast strike and northwest dip 

 bring up the Chazy, Black River and Trenton beds in succession 



