884 



HISTORICAL GEOLOGY. 



different ; and besides, those of the latter thus far make but one group for 

 the Eocene, and one for the Miocene. For these reasons, the three regions, 

 the Atlantic and Gulf borders, the Pacijic border, and the Lacustrine areas, 

 are independent in their subdivisions and cannot be satisfactorily correlated. 

 They are brought together, however, in the following table, to exhibit the 

 general relations of the subdivisions, and nothing more. It is not yet known 

 in all cases what subdivisions of the Eocene formations recognized on the 

 coast are equivalents of the Lower, Middle, and Upper Tertiary in the 

 Continental Interior. 



Table of Approximate Equivalency op the Subdivisions. 





Atlantic and Gulf borders 



Lacustrine areas 



Pacific border 



Foreign 



Pliocene 



Floridian 



Blanco 

 Palo Duro 



Pliocene 



Pliocene 



Miocene 



Yorktown 



Chipola 



Chattahoochee 



Loup Fork 

 John Day 

 White River 



Miocene 



Tortonian 

 Aquitanian 



Eocene 



Upper, Vicksburg 



Uinta 





Tongrian 

 Ligurian 



r Jackson 

 Middle -j Claiborne 



I- Lower Claiborne 



Bridger 

 Wind River 



Tejon 



Parisian, or Calcaire 

 Grossier 



( Lignitic 

 Lower - ,^.* 



( Midway 



Wasatch 

 Puerco 



Suessonian 

 Cernaysian 



a. MARINE TERTIARY OF THE ATLANTIC AND GULF BORDERS. 



3. Pliocene period, 



Floridian Epoch. Floridian of Heilprin, as modified by Dall. — 

 Merced grouj) of the peninsula of San Francisco, of A. C. Lawson. 



2. Miocene period. 



3. YoRKTOWN Epoch. So named from Yorktown, Va., Dana's 

 Geol., 1863. Chesapeake of Darton and Dall, 1891. 



2. Chipola Epoch. Eepresented by the Chipola group of Burns, 

 occurring along the Chipola River, Florida. 



1. Chattahoochee Epoch. Chattahoochee of Langdon, named 

 from typical exposures on the Chattahoochee River in southwest 

 Georgia and northwest Florida. 



1. Eocene period. 



6. Vicksburg Epoch. Vicksburg of Conrad ; named from beds at 



Vicksburg, Miss. 



5. Jackson Epoch. Jackson of Conrad, exposed near Jackson, 



Miss. 



