376 ' PALEOZOIC TIME. 



2. Ohio Section. 



Lower Silurian. 



Primordial, Potsdam Epoch. — Whitish calcareous sandstone, 3 16 feet or more — (at 



bottom of the " State House well "). 

 Canadian, Calciferous Epoch. — Drab, sandy, magnesian limestone, 475 feet — (passed 



through in boring the " State House well "). 

 Trenton, Trenton, Utica, and Cincinnati Epochs. — Limestones and calcareous shales 



and marly tes, blue and green below, gray, brown, and red above, 1,220 feet, 



(the lower 250 found only in deep borings.) 



Upper Silurian. 



Niagara, Clinton Epoch. — Cream to salmon-colored, semi-crystalline, crinoidal lime- 

 stone, 10 to 40 feet. 

 Niagara Epoch. — Shales, 60 to 100 feet, overlaid by buff and blue arenaceous 



and magnesian limestones, 90 to 180 feet. 

 Salina Epoch. — Limestones, with beds of gypsum, 1 to 16 feet. 

 Lower Helderberg. — " Waterlime " group: gray and yellow, coarse-grained and 



massive limestones, 70 to 100 feet. 

 Oriskany, Oriskany Epoch. — Coarse saccharoidal sandstone, 3 to 10 feet. 



Devonian. 



Corniferous, Corniferous Epoch. — Buff massive limestone, 15 to 100 feet. 

 Hamilton, Hamilton Epoch. — Bluish marly limestone, 10 to 20 feet near Sandusky, 

 elsewhere wanting. 

 Genesee Epoch. — Black, bituminous "Huron" shale, with numerous large 

 calcareous concretions, 250 to 330 feet. Partly Portage ? 



( " Erie " green, gray, and blue shales, with few thin lay- 

 Chemtjng, Portage Epoch. — ! ers of sandstone and limestone: 1,000 feet in the eastern 

 Chemung Epoch. — 1 counties, 500 to 400 in the central ones, and thinning 

 [ southward until no longer recognized. 



Carboniferous. 



Subcarboniferous, Lowe r. — " Waverly " shales and sandstones; in the northern 

 counties, 320 feet; 640 feet, on the Ohio River. 

 Upper. — " Maxville " limestone, 10 to 20 feet. 

 Carboniferous, Millstone Grit Epoch. — Conglomerate and sandstones, 10 to 130 feet. 

 Coal- measures. —Shales, sandstones and limestones, with bands of iron ore 

 and twelve workable seams of coal, 2,000 feet. 



8. Michigan (Lower Peninsula) Section. 



Lower Silurian. 



Primordial. — No formation certainly identified. 



Canadian. — " Lake Superior" sandstone, mottled, reddish, or dark and shaly, at 



Sault St. Mary, 18 feet; more to the westward, 250 feet. 

 Trenton, Trenton Epoch. — Blue argillaceous limestone, with shale, 30 feet. 



Cincinnati Epoch. — Argillaceous limestone, bluish-gray below, 18 feet or 



more. 



Upper Silurian. 



Niagara, Clinton Epoch. — Argillaceous and calcareous limestones, 51 feet. 

 Niagara Epoch. —White and gray limestones, 97 feet. 



