450 A. W. GRABAU PALEOZOIC DELTA DEPOSITS OF NORTH AMERICA 



about 1,000 feet thick and are separated by the Tellico sandstone from 

 250 to 500 feet in thickness. Still farther to the southeast, in the same 

 quadrangle, the Chickamauga is only 50 feet thick, but it is followed by 

 1,000 to 1,200 feet of calcareous shales, the Athens, on which rest the 

 Tellico calcareous sandstones and shales, 800 to 900 feet thick. Above 

 this follows the Sevier shale, which here has increased to 2,200 or even 

 3,000 feet (4,000 feet is the estimated thickness at the northern end of 

 Bays Mountain), and carries several heavy sandstone members. If we 

 then assume that no elimination of beds by faulting has occurred, and 

 rule out further hypothetical disconformities, we obtain about 300 feet, 

 more or less, of soft shales as the representative of the Upper Sevier in 

 this region, much of this being taken up by the concealed interval. 



The lower 130 feet of the shales appearing next above the concealed 

 interval are fossiliferous, containing Plectorthis fissicosta, Rafinesquina 

 alteniata, PJatystropliia cf. biforata, Zygospira of modesta group, Cleido- 

 pliorous cf. planiilatuni, Calymmene senwria, etcetera. This fauna is 

 essentially an Upper Lorraine or about the middle of the Maysville. 



The shales already show a reddish color, but this is not very pro- 

 nounced, nor is lime a very prominent constituent of this section. For 

 15 feet above the last fossiliferous layer the strata become more sandy 

 and somewhat more reddish. Then the cliff is covered for a distance of 

 125 feet, which with a dip of 60° would make about 105 feet of strata. 

 Throughout this distance, however, variegated clays crop out at the base 

 of the cliff. When the beds are exposed again, they are deep, brick-red 

 clays, with occasional sandstones. Xo fossils have been found in these 

 beds, which have a thickness of 40 feet. Then the section is again cov- 

 ered for a distance of 225 feet to the forking of the road. This corre- 

 sponds to a thickness of about 190 feet, though variations in the dip make 

 this only approximate. The section is continued in a stream channel 

 below the road, where appear the same brick-red shales, alternating with 

 pale-red beds. Occasionally bands of hard, greenish and red limestone 

 occur in these higher beds. They stand out in relief among the clays, 

 but no fossils have been found in them. In these limestones mud-crack 

 structures have been observed. Overlying the limestones is a series of 

 soft beds which are concealed for a distance of 250 feet, making a thick- 

 ness of 200 feet, more or less. Over most of this area, however, the rock 

 is just below the surface, which is full of fragments of a fine-grained, 

 thin-bedded sandstone derived apparently from the concealed beds. Then 

 follows the fossiliferous iron ore of the Rockwood, which, with its imme- 

 diately inclosing beds, gives a thickness of 20 feet. After this follow 





