140 THE CAMBRIAN. [bull. 81. 



series, composed of grauwacke, slaty grauwacke, sandstone, and lime- 

 stone, which extend from the Primordial series to where they are lost 

 under the Cumberland Mountains, is colored yellow, thus roughly out- 

 lining the relations of the Cambrian and pre-Cambrian rocks of east- 

 ern Tennessee. 



Before publishing the Sixth Annual Report, Dr. Troost read Murchi- 

 son's " Siluria," and also the observations of Prof. Sedgwick on the 

 Cambrian rocks of Wales. In discussing the changes of nomenclature 

 made necessary in accepting the views of Messrs. Murchison and 

 Sedgwick, he says : 



After having pointed out, in my last report, the line of junction of the Primordial 

 or crystalline rocks in East Tennessee, I mentioned that the country west of the line, 

 which separates Tennessee from the State of North Carolina, is composed of grau- 

 wacke, slate, limestone, etc. All this country, according to the views of Murchison 

 and Sedgwick, belongs to a new division, which they call the Cambrian system. 



This series of strata contains few organic remains ; in fact, I have carefully exam- 

 ined, in this respect, the Tennessee strata and have never discovered any in them. 1 



In his attempt to identify the Cambrian and Siluriansy stems in 

 Tennessee, he included rocks in the Cambrian system that, under the 

 original definition of Sedgwick for that system in Wales, is surprisingly 

 correct. In describing the geographic distribution of the Cambrian 

 system, he says : 



I consider the termination of the Cambrian System towards the west. This system 

 commences, as already observed, about the line which separates the State of Ten- 

 nessee from North Carolina ; and, as mentioned in my preceding reports, is also, with 

 a few exceptions, the line of separation between the transition and primordial strata. 

 It runs sometimes a few miles into North Carolina; sometimes penetrates, for a few 

 miles, into Tennessee, forming the great Unica or Smoky Mountain, Bald Mountain, 

 andiron Mountains; but the culminating ridge of this mountain chain is mostly 

 composed of the Cambrian rocks, while south of it the crystalline or Primordial rocks 

 are found. 



Leaving this ridge in a north, or rather northwest direction, we have a series of 

 slaty rocks, containing here and there chlorite, passing into talcose slate — or into 

 quartzite. This series seems to be equivalent to Sedgwick's Lower Cambrian series; 

 some extensive strata, mostly of brown or reddish brown, fine grained limestone 

 occur occasionally in this series; such a stratum is seen about 5 miles west from 

 the Primordial rocks, crossing, near the Warm Springs in Buncombe County, the 

 French Broad River. We have then a series of strata of slates and sandstone, and 

 about 4 or 5 miles west of Newport a limestone stratum appears again, extending 

 through Cocke and Sevier counties, iiarallel to the above-mentioned high chain. I 

 suppose the Lower Cambrian system terminates there. 



Upon the Lower Cambrian rocks follows another scries. It is composed of roofing 

 slate, glossy aluminous slate, and sandstone. A ridge of fine roofing slate crosses 

 Sevier County. I believe that this series commences with Star's, Tellico, and Chil- 

 howee Mountains in MoMinn, Monroe, and Blount counties, ranging parallel with the 

 great Smoky Mountain, extending in a southeastern direction through Sevier County. 

 I have not been able to trace it further to the northeast. This series seems to be 

 equivalent to the Middle Cambrian. * * * 



I consider, as stated above, that Bay's Mountain forms the upper part of the Cam- 

 brian system — or, that it perhaps belongs to the Old Red sandstone — that hence towards 

 — — . — 



1 Sixth annual report of the geological survey ol Tennessee, by the State geologist. Nashville, 

 841, p. 4. 



