478 THE AZOIC SYSTEM AND ITS SUBDIYISIOXS. 



tioa of Western North Carolina, as well as the adjacent regions of 

 Georgia and Alabama. In a series of papers entitled " On the Silurian 

 Age of the Southern Appalachians," (Amer. Jour. Sci., 1875, (3) IX., 

 pp. 279-288, 370-383,) this geologist reaches conclusions which he thus 

 states : — 



" The rocks of that portion of North Carolina south and west of the Little 

 Tennessee, together with the metaiuorphic area of Georgia, north of a line par- 

 allel with and ten miles south of the Chattahoochee (and frohahhj that south of 

 this line), and the entire metamorphic area of Alabama, are Silurian or newer, 

 with the possible exception of two or three small patches not over ten miles in 

 diameter." {I. c, p. 280.) 



Professor Kerr acknowledges that, if Professor Bradley's identifications 

 prove valid, it will probably be found that all the Huronian rocks except 

 those of the middle and eastern belts will prove to be Silurian. Of 

 these he remarks (/. c, p. 140) : — 



" But this conclusion will not involve the great middle and eastern belts 

 which must still remain Huronian, until determined independently to belong 

 to a later series ; both because they are widely separated from the others, and 

 because they have lithological and stratigraphical characters of their own, which 

 would prevent their following any determinations of horizon for the others, 

 which should be based on these considerations alone." 



In regard to an area adjacent to Tennessee, Professor Kerr says (/. c., 

 p. 139): — 



" This belt of rocks is colored on the map throughout like the other Huro- 

 nian belts, and for the same reasons, viz. : that they succeed the Laurentian, 

 and differ from them strongly in degree of metamorphism and general litho- 

 logical character, so that the transition from one to the other is obvious along 

 the whole extended line of contact, and that they have yielded no fossils, 

 which alone could authorize their reference to a later age. And although the 

 fact of unconformability can not be asserted for any one of the sections, this may 

 arise from the circumstance that the disturbance and dislocation of the strata 

 along this line are extreme, and that no detailed or minute examination has 

 ever been attempted, and of course nothing short of such examination would 

 suftice in such a region. And another circumstance cf weight is the inunense 

 body of these rocks, which must be allowed, on the French Broad for example, 

 after every reasonable reduction for folding, a thickness of several miles. Add 

 these to the primordial or the lowest members of the Lower Silurian, and they 

 receive a most incredible development downwards, since the rocks along the 

 Tennessee border referred to this horizon have already a very great thickness. 

 However, as stated above, these rocks have only been located 'provisionally. 

 And it is right to say further that the only examination I have made of this 

 western Smoky belt, was a mere reconnoisance, mostly on horseback, made in 

 a few weeks in the autumn of 1866." 



