National Geographic : 1894 May 23
74 Hayes and Campbell-Appalachian Geomorphology. which remnants of its surface fall into a common plane of vision. This is the case whenever the observer stands upon the level of the old arena. He may then sweep with a glance the profile of a geographic condition which has long since passed away. Again, in speaking of its altitude and probable origin, he says:* We have recognized that dissected plain, the level of the Asheville amphitheater, now 2,400 feet above the sea. It was a surface produced by subaerial erosion, and as such it is evidence of the fact that the French Broad river and such of its tributaries as drain this area at one time com pleted their work upon it, reached a baselevel. This baseleveled condition, as described by Willis on the French Broad, has been found to characterize nearly all the river valleys of the Great Smoky mountains and has been observed by the present writers on the Little Tennessee, Hiwassee and Ocoee rivers of the Tennessee system and on the Coosawattee and Etowah rivers of the Alabama system. The altitudes of the baseleveled valleys vary considerably, but on the whole show a gradual descent southwestward. Thus the altitude of the peneplain is 2,400 feet at Asheville, 2,200 feet on the Little Tennessee, 2,000 feet on the Hiwassee, 1,900 on the Ocoee and 1,600 feet on the Coosawattee. The proportion of the surface which was reduced to baselevel also increases southwestward and in northern Georgia, in place of the baseleveled mountain valleys, most of the surface was reduced and adjacent river basins merge with low divides. Thus the upper basin of the Coosawat tee and Etowah present to the eye the characteristic form of broad undulating plains partly enclosed by mountains and from which rise the gentle slopes of island-like monadnocks. In detail these plains are found to be deeply etched by the present streams, which flow in narrow recently-cut gorges several hun dred feet below their general level. On the Etowah river and southward this enclosed valley type disappears and the pene plain assumes a different form, which will be described later. Blae Ridge Type.-The writers are less familiar with the region northward from the French Broad river and the data for recon structing the Cretaceous peneplain are less abundant. The topographic maps, however, show quite strong evidence of the existence of this peneplain in the region in question, though it * Op. cit., p. 297.
1894 Jun 22
1894 Apr 25