380 PALEOZOIC TIME. 



Chemung, Portage Epoch. — " Vergent" dark-gray, flaggy sandstones, with some 



blue shale, 1700 feet. 

 Chemung Epoch. — " Vergent" gray, red, and olive shales, with gray and 



red sandstones, 3200 feet. 

 Catskill. — " Ponent" red sandstone and shale, with some conglomerate, 6000 



feet.- 



Carboniferous. 



Subcarboniferous, Loioer. — "Vespertine" coarse, gray sandstones and sili- 

 ceous conglomerate at the eastward, becoming fine sandstones and 

 shales at the westward, 2660 feet. 

 Upper. — " Umbral" fine red sandstones and shales, with some limestone, 

 3000 feet. 



Carboniferous, Millstone- Grit Epoch. — "Serai" siliceous conglomerate, coarse 

 sandstone and shale, with some fine argillaceous shales, including 

 coal-beds, 1100 feet. 

 Coal Measures. — Sandstone and shale, with some limestone, 2000-3000 

 feet. 



2. Michigan [Lower Peninsula) Section. 



Lower Silurian. 



Potsdam, Potsdam Epoch. — " Lake-Superior Sandstone," mottled, reddish, or 

 dark and shaly, at Sault St. Mary, 18 feet ; more to the westward, 

 250 feet. 

 Calciferous Epoch. — Rocks of this epoch said to exist, — character and 

 thickness not known. 



Trenton, Chazy Epoch. — Gray siliceous limestone, 2 feet. 



Trenton Epoch. — Blue and argillaceous limestone, with green calcareous 

 shale, 30 feet. 



Hudson. — Argillaceous limestone underlaid by bluish-gray subcrystalline lime- 

 stone, 18 feet or more. 



Upper Silurian. 



Niagara, Clinton Epoch. — Argillaceous, bituminous, and calcareous limestones, 



51 feet. 

 Niagara Epoch. — White and gray limestones, massive and crystalline, 



some layers arenaceous, others geodiferous, 97 feet. 

 Salina, Saliferous Epoch. — Brown and gray argillaceous limestones, calcareous 



clay, and variegated gypseous marls, 37 feet. 



Devonian. 



Oriskany, Oriskany Epoch. — Cherty, sometimes agatiferous conglomerate, 3 

 feet. 



Corniferous, Upper Helderberg Epoch. — Brecciated limestone, 250 feet ; over- 

 laid by oolitic, arenaceous, and bituminous limestones, 104 feet: total, 

 354 feet. 



