EXTENT OF FOLDING AND SUBSEQUENT EROSION 447 



years ago with reference to the age, origin, and stratigraphic significance 

 of this formation. 



The greatest thickness recorded for this formation (1,500 feet) is 

 north of Chilhowee Mountain, a mass of Cambric sandstone and con- 

 glomerate thrust over the Ordovicic strata. This is in Blount County, 

 Tennessee, on the southeast corner of the Loudon quadrangle. The for- 

 mation rests on the Sevier shale, which here is 2,000 feet or more thick 

 and has several members of calcareous sandstone and some limestones. 

 In character the Bays is here a somewhat calcareous red sandstone, with 

 more or less feldspathic material and some white sandstone members. It 

 is succeeded by the Clinch sandstone, which for the most part had been 

 eroded in pre-Chattanooga time. Northwestward in this quadrangle the 

 formation disappears by erosion, though here and there patches remain. 

 These are generally rather calcareous. The Clinch is also absent in this 

 region and the Eockwood, largely composed of the waste of the Clinton 

 and Bays, rests on the erosion remnants or on lower formations down to 

 the Chickamauga limestone. 



It is a remarkable fact that nowhere west or south of this locality, in 

 Tennessee, Georgia, or Alabama, is there any remnant of the Bays or the 

 Clinch recorded. Throughout this section the Eockwood, composed 

 largely of the debris of these formations, rests on the eroded surface of 

 the Chickamauga limestone, or its shale equivalent, the Athens. Since 

 the Eockwood is essentially Niagaran, except where it includes Medina 

 and Clinch, a great amount of erosion is indicated for post-Bays-pre- 

 Eockwood time, for not only have the southward and westward extension 

 of the Clinch and Bays been removed, but also the whole of the Sevier 

 shale, which in the Chilhowee Mountain region has a maximum thickness 

 of 2,300 feet. From this we must conclude either that the Eockwood is 

 of late Niagaran time or that it includes the true Medina at its base 

 formed from the erosion of the eastward extension of the Bays, but not 

 of the Clinch.* This will be more fully discussed in a later section. 



In the southern extension of Bays Mountain, 8 or 10 miles southeast 

 of Knoxville, Tennessee, the formation rests on the Sevier shale, which 

 is here 1,200 feet or more in thickness. The Bays itself is not fully 

 preserved, only from 300 to 500 feet occurring, this constituting the 

 highest formation of the region. It is probably only the lower calcareous 

 member of the series which is here seen. Southeastward, however, in 



* TJlrich has since shown thai the typical Rockwood of southeastern Tennessee in- 

 cludes "representatives of the Juniata and of all the distinguishable members of the 

 Upper Medina in New York, bu1 that it docs not Include beds of Clinton age." (Ball, 

 Geol. Soc. Am., vol. 24, p. 108.) 



