378 PALEOZOIC TIME. 



5. Illinois Section. 

 Lower Silurian. 

 Canadian, Calciferous Epoch. — " Lower Magnesian limestone," 100 to 120 feet. 



Chazy Epoch. — " St. Peter's " sandstone, 150 feet. 

 Trenton, Trenton Epoch. — " Trenton " and " Galena " brown magnesian limestones, 

 200 to 300 feet. 

 Cincinnati Epoch. — Shales, shaly sandstones, and dark-blue limestone. 60 to 

 250 feet. 



Upper Silurian. 



Niagara. — Buff and gray magnesian limestone, some cherty beds, 250 to 300 feet. 

 Lower Helderberg ? — «' Clear Creek " limestone, 300 to 350 feet. 

 Oriskany. — Quartzose sandstone, becoming locally calcareous, 50 feet. 



Devonian. 



Corniferous ? — Limestone, 10 to 120 feet. 



Hamilton, Hamilton Epoch. — " Black shale," 30 to 60 feet. 



Carboniferous. 



Sue-carboniferous. — Consisting of — 1st, "Kinderhook" group, 100 to 150 feet;. 

 2d, "Burlington" limestones, with chert, 25 to 200 feet; 3d, "Keokuk" 

 group, 100 to 150 feet; 4th, "St. Louis" group, 50 to 200 feet; 5th,. 

 " Chester " group, 500 to 800 feet. 



Carboniferous, Millstone Grit and Coal-measures, 600 to 1,200 feet. 



6. Missouri Section. 

 Lower Silurian. 



Canadian, Calciferous and Quebec Epochs. — "Lower Magnesian " limestones, 1,300— 



1,500 feet. 

 Trenton, Trenton Epoch. — Bluish -gray and drab compact limestone, and some blue 



shale, 435 feet; overlaid by " Receptaculite " argillaceous subcrystalline- 



limestone, 130 feet; total, 565 feet. , 

 Cincinnati Epoch. — Two beds of argillaceous magnesian limestone, 60 feet, 



separated by shales, 60 feet; total, 120 feet. 



Upper Silurian. 



Niagara, Niagara Epoch. — Magnesian and argillaceous limestone, 150 feet. 

 Lower Helderberg. — Light-gray magnesian limestone, 100 feet. 

 Oriskany. — Light-gray, nearly pure limestone, — thickness not given. 



Devonian. 



Corniferous. — Gray, compact, earthy limestone, with chef t and some sandstone ; in 

 some parts, a hard white oolyte, 75 feet. 



Hamilton, Hamilton Epoch. — Blue argillaceous shale, with thin layers of concretion- 

 ary limestone, 50 feet. 

 Genesee Epoch. — " Black shale," 6 feet. 



Carboniferous. 



Subcarboniferous. — 1st, Light-drab, fine-grained, compact, "Lithographic " siliceous 

 limestone, 70 feet; 2d, buf£ sandstone, with some magnesian limestone, 



