GENERAL OBSERVATIONS. 379 



underlaid by shale, 100 feet; 3d, fine-grained, compact limestone, overlaid 

 by brown silico-magnesian limestone, 70-120 feet; 4th, "Encrinital," brown, 

 buff, gray and white, coarse crystalline heavy-bedded limestones, every- 

 where containing chert, 500 feet; 5th, "Archimedes " gray and drab, crys- 

 talline and compact limestones, with some silico-argillaceous limestones 

 and blue shales, 200 feet; 6th, "St. Louis" hard, crystalline, gray, cherty 

 limestone, with thin beds of argillaceous shale, 250 feet; 7th, "Ferru- 

 ginous " brown and red, coarse, friable sandstone, in some parts white and 

 "saccharoidal," 200 feet: total, 1,150 feet. 

 Carboniferous, Coal-measures. — Blue and gray compact limestones, with blaek, 

 blue and purple bituminous and calcareous shales, and a few thin beds of 

 coarse sandstone, 2,000 feet or more. 



7. Tennessee Section. 



Lower Silurian. 



Primordial, Acadian Epoch (?). — " Ocoee " slates and conglomerates, 8,000 to 

 10,000 feet. 

 Potsdam Epoch. — "Chilhowee" sandstones and sandy shales, at least 2,000 

 feet in East Tennessee. 



Canadian, Calciferous and Quebec Epochs. — " Knox Group," fine-grained sandstones 

 and shales, with magnesian limestone: sandstone member (lowest), 800-1,000 

 feet in East Tennessee; shales, 1,500-2,000 feet; limestone, 3,500 to 4,000 

 feet. 



Trenton, Trenton Epoch. — Blue and dove-colored limestones, gray and mottled mar- 

 bles and shales, 1,500-2,000 feet in East Tennessee ; Trenton and lower part 

 of "Na'shville Group," 500 feet in Middle Tennessee. 

 Utica and Cincinnati Epochs. — Upper part of "Nashville Group," calcareous 

 shales and argillaceous limestones, including beds of fine marble, 500-1,000 

 feet in East Tennessee ; 500 feet in Middle Tennessee. 



Upper Silurian. 



Niagara, Medina Epoch. — " Clinch Mountain " white and gray sandstone, and 

 " White Oak Mountain " brown sandstones and shales, 800-1,000 feet. 

 Clinton Epoch. — " Dyestone Group," variegated calcareous shales, with some 

 sandstone and bands of ; ' dyestone " iron-ore, 100-300 feet in East Tennessee. 

 Niagara Epoch. — " Meniscus " gray limestone, 150-200 feet. 

 Lower Helderberg. — Gray crinoidal limestone, 75-100 feet in Middle Tennessee ; 

 absent elsewhere ( ?). 



Devonian. 



Hamilton ( ?), Genesee Epoch. — " Black shale," a brownish-black shale, often pyrit- 

 iferous and bituminous, with a layer of phosphatic nodules at top, and a 

 dark gray, fine-grained bituminous fetid sandstone at bottom, 100 feet or 



Carboniferous. 



Subcarboniferous, Lower. — " Siliceous Group," shales and sandstone, varying to 

 blue and gray limestones, mostly cherty, with some shale, 300-550 feet. 

 Upper. — "Mountain" limestone, blue, thick-bedded, and in great part 

 oolitic, 500-700 feet in Middle Tennessee. 



Carboniferous. — Sandy conglomerates, sandstones and shales, with six or more 

 workable coal-beds, 2,500 feet or more. 



