300 THE CAMBRIAN. fBuu.8l. 



separated horizons. The latter is the fact. The Chilhowee formation in Chilhowee 

 Mountain has been proved by fossils to be Lower Cambrian, but it is a synclinal 

 mass isolated by faults, and the definite determination does not apply beyond its 

 limits. It is not connected with the Ocoee area, and the Ococe rocks in the type 

 locality are so separated from strata of known age, that nothing definite can now be 

 asserted as to their correlations. Starrs Mountain, a " Chilhowee" outlier 24 miles 

 southwest of Chilhowee Mountain, contains a fossiliferous limestone apparently con- 

 formably underlying the quartzite ; if further study coufirms this apparent relation, 

 the quartzite is near or above the top of the Lower Siluriau. Meadow Creek Moun- 

 tain and the Big Butt range, extending from 25 to 70 miles east by north from Chil- 

 howee Mountain and assigned by Safford to the Chilhowee and Ocoee formations, are 

 determined on stratigraphic and structural evidence to belong to the Nashville period, 

 the last of the Lower Silurian deposits. " Ocoee" strata of Safford, occurring south- 

 east of Chilhowee Mountain about Cades, Tuckaleechee, and Weirs Coves, are known 

 to belong to the Nashville on evidence of strict structural conformity to the Knox 

 dolomite over three extensive quaquaversals and through transition beds from the 

 dolomite to the slates. The Nashville " Ocoee" strata in this locality and in the Big 

 Butt exceed 12,000 in thickness and form some of the highest ranges along the North 

 Carolina boundary. 



If, as these facts prove, the great natural group of elastics along the eastern Paleo- 

 zoic border is the result of conditions repeated in different periods, we should seek 

 an explanation for recurrence of like conditions, and this is found in the relative 

 extent of subsidence in the Cambrian and Silurian times. 



The Cambrian sea transgressed over the granitic continent under such conditions 

 that the constituent minerals entered into shore deposits, without complete decom- 

 position; these conditions probably existed in the deep disintegration of the granite, 

 as suggested by Pumpelly. The subsidence ceased during Knox time and the depo- 

 sition of the Knox was followed by uplift which exposed the dolomite to the waves 

 of the Nashville sea. The evidence of this and of subsequent subsidence is found 

 in conglomerates of Knox dolomite at the base of and interstratified with the strata 

 of the Nashville-Ocoee in many localities. The beds associated with these conglom- 

 erates are arenaceous shales and sandstones, but higher in the Nashville series con- 

 formably stratified with these, and extending to basal conglomerates resting on the 

 Archean, are deposits containing granitic fragments like those of the Cambrian- 

 Ocoee. The stratigraphic and geographic relations leave no doubt that the Nash- 

 ville was a period of great transgressions beyond the limits of any previous subsi- 

 dence, and the deposits derived from the granites in the later time were identical 

 with those earlier accumulated from the same source. 



The semi-metamorphic character of both Cambrian and Nashville-Ocoee strata 

 demands explanation which may possibly be found in their original composition and 

 in their common relations to thrust and resistence during Appalachian formation. 

 Both series of rocks are thin bedded piles, both rest against the unyielding Archean 

 masses. Whatever pressure they received they were forced to conform to and they 

 appear to have suffered changes of form, which were both mechanical and chemical 

 and which were induced by dynamic conditions. 



The generalizations herewith submitted are derived from the detailed work of 

 Messrs. Arthur Keith and C. Willard Hayes as well as from my own studies and the 

 conclusions as to the age of formations have been reached through mutual coopera- 

 tion. 



Chilhowee sandstone. — The lithologic character of the Chilhowee sand- 

 stone is given as follows by Prof. Safford : 



It is a great group of heavy-bedded sandstones, often dark, but generally weathering 

 to a grayish white, and containing great beds of whitish quartzose sandstone, or quartz- 

 ite. Interstratified with the heavy -bedded rocks are, at some points, sandy shales, 

 and thin flags, often containing scales of mica. Some of the sandstones are coarse 



