66 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



nected with the Central Basin of Tennessee. The Sequachee Valley 

 in Eastern Tennessee belongs to this class. The Sequachee Valley is 

 a long narrow valley pursuing a straight southwesterly course for 

 about seventy miles, with an average width of about four miles, and 

 enclosed between two escarpments of from 800 to 1000 feet in height. 

 The head of the valley lies within the Cumberland Tableland, in fact 

 Sequachee Valley breaks the Cunii)erlaiid Tableland into two divi- 

 sions ; and the mouth may be said to debouch into the Valley of the 

 Tennessee River, near where the boundary lines of Georgia and 

 AlaVjama meet the Tennessee line. In going eastward from the 

 margin of the Central Basin, the Sequachee fold is the first great fold 

 met with. It forms the Crab Orchard Mountain at its north-eastern 

 end, and by a continuation southwesterly it is exhibited in the 

 Sequachee Valley which is simply the fold with the upper portion of 

 the plications worn off owing to fracture, admission of watei-, and 

 con.sequent erosion. 



In the same line of folding thei-e is a small basin "Grassy Cove "^ 

 formed in a similar manner, but Grassy Cove is completely sur- 

 rounded by hills. 



Another good instance of a valley of elevation is to be found in the 

 Jones and Roup's Valley in Alabama, and lying between the Coal 

 Basin of Warrior on the west, and that of the Cahaba on the east. 

 Dr. Smith (Geological Survey of Alabama, 1876, p. 14) says: "The 

 rugged barren hills of the coal fields contrast sti'ikingly with the roll- 

 ing fertile lands of the valley, and we have presented here, as has 

 been remarked Vjy Professor SafFord, the curious case of a valley 

 which is higher than the mountain. The geological structure of th& 

 region is in general as follows : In the middle of the valley the sti'ata 

 belong to that sub-division of the Lower Silurian which I have called 

 Quebec or Knox Dolomite ; these rocks are found dipping generally 

 towards the south-east, though in many places they dip both north- 

 west and south east. Crossing from the centre of the valley south-east 

 towards the Cahaba coal fields, we go over the rocks of the Chazy and 

 Trenton, the Niagara, the Black Shale, the Sub-carboniforous, the 

 Millstone Grit and the shales and sandstones of the coal measures 

 all lying conformably and dipping south-east. Gkjing north-westward 

 we find the same succession of strata up to the coal measures of the 

 Warrior fields, the dip being sometimes north-west, though often. 



