18 CLASSIFIED KEY TO THE INDEX. [bull. 135. 
Page. 
Ohio ... 123 
Oklahoma 123 
Oregon 123 
Paleontology 123 
Cambrian 123 
Silurian 123 
Devonian 124 
Carboniferous 124 
Juratrias 124 
Cretaceous 124 
Tertiary, miscellaneous 124 
Eocene 124 
Miocene 125 
Pliocene 125 
Pleistocene 125 
Miscellaneous 125 
Genera and species described 125 
Pennsylvania 137 
Petrology 137 
Arizona 137 
Arkansas 137 
California 137 
Canada 137 
Colorado 137 
Guatemala 137 
Maryland 137 
Massachusetts 137 
Michigan 137 
Minnesota 137 
Missouri 137 
Montana 137 
New Jersey 137 
New York , 137 
Rhode Island 137 
South Dakota 137 
Vermont 138 
Virginia 138 
Miscellaneous discussions 138 
Rocks described 138 
Physiographic geology 138 
Pleistocene (not relating to glacial deposits) 139 
New York 139 
Atlantic Coastal Plain 139 
Great Lakes region 139 
Mississippi Valley 139 
Gulf States 139 
Rocky Mountain region 139 
Sierra Nevada and Pacific Coast region 139 
Alaska 139 
Miscellaneous 139 
Rhode Island 139 
Silurian 139 
Canada 139 
Noav England 139 
Appalachian region 139 
