478 ON THE PHYSICAI, STRL'CTrRE 



bounds it on the northwest, may be stated at about thirty-five 

 miles. This portion of the chain embraces all the upper Appa- 

 lachian formations, including the whole of the carboniferous 

 gi-oup. 



Following the course of this great mountain belt from Canada 

 to Alabama, it will be seen to consist of a series of nine straight 

 and curved portions in alternate succession, distinguished from 

 one another by important topogi'aphical features, as well as by 

 peculiarities of geological structm'e, and forming' nine distinct 

 divisions. 



1. Of these the first, or Hudson River Division, extends from 

 Canada to New Jersey, following the general course of the Hud- 

 son as far as the Highlands in New York, and comprising not 

 only a large area in the eastern and northern parts of that Slate, 

 but a considerable tract in western Vermont and Massachusetts. 

 Along the great valley, from the northern part of Vermont to the 

 passage of the Hudson through the Highlands, the strike of the 

 rocks, and the direction of the axes, is about north fifteen degrees 

 east, and south fifteen degrees west. 



■2. From where the Hudson crosses the Highlands, to the 

 Lehigh river in Pennsylvania, the whole chain bends gi-adually 

 westward, taldng a long and regular sweep concave to the north- 

 west. This portion of the chain we propose to call the Delaicare 

 Division. 



3. The next is a nearly straight part of the chain ; extending 

 from the Lehigh river to Cumberland county, in Pennsylvania, 

 and may very properly be named the Susquehanna Division. 

 Throughout this tract the strike is from, east-northeast to west- 

 southwest. 



4. To the southwest of the foregoing is the higlily interesting 

 curving portion of the chain, which we shall call the Juniata 

 Division. This diversified region extends from about twenty 

 miles west of the Susquehanna, to nearly the same distance north 

 of the State line of Maryland, and is cliaractcrized by a regular 

 and very decided curvature, convex towards the northwest. The 

 formations, in ranging betAVcen the above limits, change iheir 

 strike from south seventy degrees west, to south thirty degrees 



