2o8 HISTORICAL PALEONTOLOGY. 



GENERAL TABLE OF FRENCH EOCENE STRATA. 

 UPPER EOCENE. 



French Subdivisions. English Equivalents. 



A. i. Gypseous series of I. Bembridge series. 



Montmatre. 

 A, 2. Calcaire silicieux, or 2. Osborne and Headon series. 



Travertin Inferieur. 



A. 3. Gres de Beauchamp, or 3. White sand and clay of 



Sables Moyens. Barton Cliff, Hants. 



MIDDLE EOCENE. 



B. I. Calcaire Grossier. i. Bagshot and Bracklesham 



B. 2. Soissonnais Sands, or beds. 



Lits Coquilliers. 2. Wanting. 



LOWER EOCENE. 



C. i. Argile de Londres at i. London clay. 



base of Hill of Cassel, 



near Dunkirk. 

 C. 2. Argile plastique and lig- 2. Plastic clay and sand with 



nite. lignite (Woolwich 



and Reading series). 

 C. 3. Sables de Bracheux. 3. Thanet sands. 



III. EOCENE STRATA OF THE UNITED STATES. The low- 

 est member of the Eocene deposits of North America^ is the 

 so-called " Lignitic Formation," which is largely developed in 

 Mississippi, Tennessee, Arkansas, Wyoming, Utah, Colorado, 

 and California, and sometimes attain a thickness of several 

 thousand feet. Stratigraphically, this formation exhibits the 

 interesting point that it graduates downwards insensibly and 

 conformably into the Cretaceous, whilst it is succeeded uncon- 

 formably by strata of Middle Eocene age. Lithologically, the 

 series -consists principally of sands and clays, with beds of lig- 

 nite and coal, and its organic remains show that it is principally 

 of fresh-water origin with a partial intermixture of marine beds. 

 These marine strata of the " Lignitic formation ' ; are of special 

 interest, as showing such a commingling of Cretaceous and 

 Tertiary types of life, that it is impossible to draw any rigid 

 line in this region between the Mesozoic and Kainozoic sys- 

 tems. Thus the marine beds of the Lignitic series contain 

 such characteristic Cretaceous forms as Inoceramus and Am- 



