288 HISTORICAL PALEONTOLOGY. 



the Isle of Wight be placed in the Middle Eocene, the only 

 British representatives of the Upper Eocene are the Bembridge 

 beds. These strata consist of limestones, clays, and marls, 

 which have for the most part been deposited in fresh or brack- 

 ish water. 



II. EOCENE BEDS OF THE PARIS BASIN. The Eocene 

 strata are very well developed in the neighbourhood of Paris, 

 where they occupy a large area or basin scooped out of the 

 Chalk. The beds of this area are partly marine, partly fresh- 

 water in origin ; and the following table (after Sir Charles 

 Lyell) shows their subdivisions and their parallelism with the 

 English series : 



GENERAL TABLE OF FRENCH EOCENE STRATA. 

 UPPER EOCENE. 



French Subdivisions. English Equivalents. 



A. I. Gypseous series of Mont- I. Bembridge series. 



martre. 



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



vertin Inferieur. 



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



Sables Moyens. Cliff, Hants. 



MIDDLE EOCENE. 



B. I. Calcaire Grassier. I. Bagshot and Bracklesham beds. 



B. 2. Soissonnais Sands, or Lits 2. Wanting. 



Coquiliiers. 



LOWER EOCENE. 



C. I. Argile de Londres at base of i. London clay. 



Hill of Cassel, near Dun- 

 kirk. 



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

 nite (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 attains 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. 



