46 MEMOIRS NATIONAL ACADEMY OF SCIENCES. [voL.xn. 



And Hayes and Campbell ('94, p. 103) state that: 



In the central portion of the province the Cumberland River probably drained a portion of the Appalachian Valley 

 in Southwestern Virginia, holding its antecedent course through Cumberland Gap and flowing into the extreme end of 

 the Mississippi embayment. 



It should be stated that at this time Campbell was of the opinion, previously expressed by 

 Hayes and Campbell ('94, p. 103), that most of the valley drained to the southward as an axial 

 stream the Appalachian River. But, as previously mentioned, Johnson's ('05) recent inves- 

 tigations do not support the southward course of this stream to the Coosa River, but indicate 

 a westward flow, as in the case of the present course of the Tennessee. The denudation of this 

 valley is thus probably very much slower than that assumed by Hayes and Campbell, and this 

 view further favors the conception that the area of Cumberland drainage in the upper part of 

 the valley was greater than has been previously assumed. 



Let us consider some of these hypothetical drainage features in greater detail. At this 

 time the Hiwassee may have been the main stream working upon the Tennessee outlet to the 

 west. The maia drainage from the mountains farther north was by the Emory River route — 

 Loudonensis River — and may have formed the trunk line of the lower Cumbei'land drainage, a 

 rather direct route. The remainder of the valley drainage was perhaps through Cumberland 

 Gap — Fluviahs River, although an apportionment of the drainage between the Emory and Cum- 

 berland Gap is very difficult to make. The location of transverse sections of the streams, the 

 general stream courses, gaps and such rehcts, are the main clues to such an interpretation. In 

 addition to the Powell, which was tributary to Cumberland drainage, other streams to the east 

 may have belonged to this same system. Davis ('91, p. 577) cites the anomalous course of the 

 Clinch across Lone Mountain (MaynardviUe, Term., sheet) as due to its location on the Cretaceous 

 peneplain. The Clinch may have turned north at this point and joined the Powell and Cum- 

 berland Rivers, as indicated in Plate 57 B. It is probable that most of the course of the river 

 has been determined by other later conditions. East of Clinch River lies the remarkable base- 

 leveled crest of Clinch Mountain, which marks the present level of this remnant of the Cretaceous 

 peneplain. This resistant sandstone mountain is notched in several places, but particidarly at 

 Big Moccasin Gap (EstUlville sheet), where a fault occurs. This is a water gap, plate 59, which 

 as Campbell remarks, is : 



The only water gap in Clinch Mountain in a distance of 150 miles. 



This gap is in alignment with the Watauga and the South Fork of the Holston, and shows 

 how the upper Holstcn drainage might have been tributary to the Clinch at Clinchport, as 

 indicated in Plate 57 C. The aUgnment of the Nolichucky also suggests that it may, at this 

 time, have been tributary to the CUnch-Cumberland. 



The French Broad, Little Pigeon, and Little Tennessee, and possibly parts oi the lower 

 covirses of the Clinch and Holston, may have all combined to flow to the westward from Kings- 

 ton, as the alignment of most of these is in harmony with such a direction. 



In this connection it is well to mention again that the tendency toward relatively adjusted 

 drainage is a characteristic feattire of a peneplain; and further, that great changes are likely to 

 follow any marked disturbance of such an equilibrium (Cf. Campbell, '96, p. 665), as when a 

 region is uplifted. , 



3. THE TERTIARY PENEPLAIN AND ITS DRAINAGE DEVELOPMENTS. 



The prolonged relative stability of the land surface which made possible the formation of 

 the Cretaceous peneplain, was checked and its destruction initiated by crustal uplifts in the early 

 Tertiary, before the Columbia depression. This upward movement, however, was not uniform, 

 according to Hayes and Campbell ('94, pp. 79, 88), but one which varied so that these authors 

 have been able to recognize, in addition to the general uplift of the region, more or less distinct 

 axes of elevation and depression. Two of these are transverse; the northern upHft, the Cincin- 

 nati-Hatteras axis, Ues at about the course of the New-Kanawha River, plate 56, and the other 

 at the southern limit. The Memphis-Charleston axis of upUft and depression is roughly parallel to 

 the westward-flowing portions of the Tennessee River in northern Alabama, A B. There are also 



