86 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



The Appalachian Mountains are composed of a series of parallel 

 waves having a general direction similar to the coast line of the 

 Atlantic Ocean. The line of maximum disturbance is on their east- 

 ern limits ; consequently their folded flexures with the inversion of 

 their steep sides are chiefly confined to the great Appalachian valley 

 and the Atlantic slope south of it. The flexures of this type impaii; 

 a prevailing south-east dip to the whole outcrop. The flexui-es of the 

 second type vv^hich curve more rapidly on the one side than the other, 

 prevail wherever the forces that disturbed the crust were neither 

 excessively intense nor very feeble. It is the characteristic form 

 everywhere between the great Appalachian valley and the Alleghany 

 Mountains. Undulations of the first or symmetrical type occur beyond 

 the Alleghany Mountains where two groups of them may be dis- 

 tinguished, the one set dividing the bituminous coal field into six 

 successive basins, and the other composed of four equidistant and very 

 straight undulations. 



These Mountain ranges were apparently raised by an intense i)res- 

 sure exerted from the east. 



The long narrow line of upheaval passing tlu'ough Kentucky and 

 Tennessee lying to the west of the Cumberland Mountains, had its 

 summit crowned by the upper beds of the sub-carboniferous. These 

 beds may have been fractured along the summit of upheaval, and in 

 this way give origin to the denuding agents which planed down the 

 area covered by the siliceous beds and ultimately hollowed out the 

 basin of Central Tennessee. 



Agents at Work in the Formation of the Central 

 Basin of Tennessee. 



The basin of Central Tennessee began to be formed as soon as the 

 sub-carboniferous beds which former-ly overlaid the whole district first 

 emerged from the waters of the sub-carboniferous ocean, and its con- 

 struction has been going on ever since. The woi-k of erosion, and 

 consequent degradation of the land, attacks the highest points first, 

 and as soon as these rocks were laid bare by an elevation the work 

 began. The elevation becoming greater, the work of erosion and 

 degradation kept on until now. When we consider the enormous 

 amount of denudation which had taken place before the excavation 

 of the main basin began, we are apt to reason that no known cause 



