OF THE APPALACHIAN CHAIN. 479 



west, undergoing thus a deviation in their course of forty 

 degrees. 



5. The next division is one of straight or nearly straight axes. 

 It extends from the southern counties of Pennsylvania, to the 

 southern side of Augusta, Pendleton, and Randolph counties, in 

 Virginia, with a strike of the rocks about north thirty east, or 

 south thirty west. This we shall call the Potomac Division. 



6. The portion of the chain next succeeding, has a decided 

 siveep, concave towards the northwest. It extends from the 

 southern limit of the previous one to the New river, and, being 

 extensively watered by the tributaries of the James river, may be 

 designated as the James River Division. The belt here referred 

 to differs from the three last, in possessing a less symmetrical to- 

 pography, and a less regular strike in its strata. Its axes are also 

 shorter and less perfectly parallel, and the whole tract is consid- 

 erably narrower, the width, from the Blue ridge northwestward, 

 across which the undulations of the strata extend, not exceeding 

 sixty miles. 



7. The division next in order, which is one of straight axes, 

 commences northeast of the New river, in Virginia, and extends 

 nearly to the mouth of the Holston, in Tennessee. Being watered 

 for a gi'eat distance longitudinally, by the latter stream, it may be 

 appropriately named the Holston Division. Both in the style of 

 the topography, and the phenomena connected with the dipping 

 of the strata, this is one of the most remarkable parts of the chain. 

 The direction of its axes and faults is about north sixty-seven 

 east, and south sixty-seven west. Its length exceeds two hun- 

 dred miles, but its breadth is somewhat inferior to that of any of the 

 previous divisions, not amounting to more than fifty-five miles 

 from the Blue ridge to the most northwestern axis. 



8. At the southern termination of the belt above described, 

 near the mouth of the Holston, commences the next division of 

 the chain. This has a curving outline, concave towards the 

 northwest, the direction of the axes and the strike of all the strata, 

 gradually changing from south sixty-seven west, to south thirty- 

 five west, making a deflection of thirty-two degrees. Traversing 

 the central parts of eastern Tennessee, and including in it the 



