THE CENTRAL BASIN OF TENNESSEE. 75 



miles, into the plateau and finishing with a waterfall. In some of 

 the channels, latei'al ones, due to smaller sti-eams flowing over the face 

 to join the main sti-eam, are cut into the hill foi- a considerable depth. 

 These jjorcfes, or channels, arive the hisrh wall surrounding the basin 

 a serrated, or fringed appearance. This, however, is a peculiarity not 

 confined to the margin of the Highland Kim but is also characteristic 

 of the various formations occupying the lower levels within the centre 

 of the basin. 



On the eastei'n side tlie Caney Fork has cut into the Rim a very ex- 

 tensive valley running in a southeasterly direction about eig'iteen 

 miles, with a width of between four and five miles. This is the most 

 extensive gap along the eastei-n escarpment. The Duck Eiver has 

 also cut a gorge, and in the southeastern corner the Elk River is 

 forming a pretty extensive valley. 



The western escarpment is much more broken than the eastern. 

 The Harpeth River has formed a channel of considerable width and 

 length, while the Duck River before entering the gorge through 

 wliich it esca|)es to join the Teimessee has formed a broad deep valley 

 with several lateral gorges opening into it both from the north and 

 the south. 



Along the southern end of the basin there is a very much broken 

 ridge of land having the same elevation as 'he Rim. This ridge, 

 which is known as the Elk Ridge, passes througli the counties of 

 Moore, Marshall, Giles, and Lewis, and forms a division between the 

 basin of the Elk River and the body of the main basin itself It is, how- 

 ever, broken through in two places — the valley in Moore county in 

 which Lynchburg is situated and the valley utilized by the Louisville 

 and Nashville Railroad running south from Columbia. 



Throughout the basin at several points the summit reaches the 

 same elevation as that of the rim, and the structure of the exposed 

 rock formations is the same. In addition to the Elk Ridge, the most 

 noteworthy place in which these summits are found is a tract running 

 along the eastern boundai'y thiough the Counties of Dekalb, Wilson^ 

 and Rutherford, where these hills form a line running nearly parallel 

 to the axis of the valley for sixteen miles when the line turns, and 

 <br al)0ut twelve miles runs in a north-westerly and south-easterly 

 dir<'ction. 



