lO NEW YORK STATE MUSEUM 



wall 1600 feet high, forming, in the vicinity of the Hudson river 

 gateway, Storm King mountain and Breakneck ridge. The southern 

 boundary on the west side of the Hudson river is a similar wall, 

 where the crystallines are faulted against the Paleozoics and 

 Mesozoics. On the east side of the river, however, the Precambrian 

 rocks decline more gently toward the south and continue to the limits 

 of the quadrangle. The West Point quadrangle therefore bridges 

 across the whole Highland belt from north to south, and includes 

 a small amount of the characteristic physiographic and geologic 

 features of the areas bordering the Highlands on both sides. 



The country changes from low and gently rolling in the southeast 

 quarter to rugged and mountainous in the west and northwest third, 

 where it is characterized by narrow, steep ridges and straight, nar- 

 row valleys with a general northeast to southwest trend. This 

 habit of relief, strikingly exhibited by such mountain ridges 

 as Breakneck mountain or by such valleys as that of Peekskill 

 Hollow creek, is so regular that it suggests at once some funda- 

 mental structural control in the geology. Here and there more 

 independent masses rise as prominent mountains without any marked 

 ridge habit. Such are Dunderberg and Anthony's ,Nose, the sentinels 

 of the southern gateway. Storm King and Breakneck at the northern 

 gateway, however, are parts of one strong ridge trenched by the 

 Hudson river so that the two parts now appear as independent 

 mountain ridges. The average surface elevation changes from 200 

 to 300 feet in the south to iioo to 1200 feet in the north. The 

 highest individual points are: Dunderberg, 1150 feet; Anthony's 

 Nose, 900 feet; Crows Nest, 1396 feet; Storm King, 1340 feet; 

 Bull Hill, 1425 feet; South Beacon, 1635 f^t. 



Across this rough, somewhat mountainous country the irregular 

 Hudson river trench or gorge, one-half to one mile wide, extends 

 from Storm King southward to Dunderberg, its walls rising sharply 

 from the water's edge. Both north and south of the mountains the 

 Hudson valley widens out to several miles. 



An interesting feature of the Hudson gorge is the occurrence of 

 small rocky islands, some of which are connected with the mainland 

 by low swampy ground. The origin of the islands, which are rather 

 unusual in a river of the age and character of the Hudson, will be 

 discussed in a later chapter on the physiographic history of the area. 



The most remarkable erosion feature of the area is the Hudson 

 trench through the Highlands, for the Hudson river shows here the 

 most extraordinary features of its whole course. 



