CRETACEOUS PENEPLAIN IN CAROLINA. 563 



Director of the United States Geological Survey (1886), plate LVI. A topo- 

 graphic elemeDt so distinct as the plateau is thus far, and extending over so 

 large an area, may confidently be expected to continue yet farther; and, with 

 study in the field, or examination of topographic maps, when such are pub- 

 lished, it will probably be traced all across Virginia. 



lu Carolina we fortunately have a very specific account of the upland in 

 question. An article by Willis, entitled " Round about Asheville," pub- 

 lished in the National Geographic Magazine,* describes the occurrence of 

 broad uplands among the mountains of North Carolina. The higher sum- 

 mits of the mountains rise indeed several thousand feet above the upland ; 

 the deeper valleys are cut five hundred or more feet below it ; but when 

 standing at the altitude of the upland surface, its parts all fall in line. A 

 view of this upland is given in Bulletin 52 of the United States Geological 

 Survey (1889), plate II. The considerable remnants of Cretaceous moun- 

 tains in this district may be ascribed iu part to the greater hardness of the 

 rocks, and also to their greater area. Willis suggests that the "balds," as 

 the broad summits of the mountains are called, represent remnants of an 

 even older baseleveled surface ; perhaps corresponding to the era of Triassic 

 degradation, here elevated but not greatly tilted or faulted by the post" 

 Triassic disturbance. The comparatively enclosed position of the Asheville 

 upland, with mountains rising above it on nearly all sides, excludes the 

 possibility of its being a plain of ma^-ine denudation. 



On the eastern side of the same mountain mass, Kerrf has described an 

 even upland in the Piedmont region of North Carolina that presumably 

 belongs with the peneplain under consideration, but demonstration of identity 

 is wanting as yet. 



Passing still farther southward the crystalline area siuks below^ the Creta- 

 ceous beds of southern Georgia and Alabama, thus confirming the date of 

 the peneplain as already determined in New Jersey. The same fate over- 

 comes the southwestern extension of the other divisions of the Appalachians — 

 the great valley, the linear ridges, and the plateau. The Cretaceous cover 

 once probably reached further north^vard over the older formations than 

 now, and here, through the Carolinas aud Virginia, as in the north, its ex- 

 tension must be tested by the arrangement of the river courses. 



Owing to the small number of maps yet published for the greater part of 

 the large area now reviewed, and also to the small attention that has yet 

 been given to its topographic evolution, it is impossible to describe with any 

 definiteness the various parts of the peneplain beyond Pennsylvania. Its 

 more precise observation offers an excellent field for research. 



From this subject we pjust now turn to the next division of the history of 



* Vol. I, 1889, pp. 291-300. 



t Amer. Jour. .Sci., 3d ser., vol. XXI, 1881, p. 21G. 



