CHAP. XI.] HANTONIAN PERIOD. 213 



limestone (Calcaire de la Beauce), which is believed to be 

 newer than our highest Hempstead clays ; it appears to be 

 of lacustrine origin, and it covers a large area between the 

 basins of the Seine and the Loire. The whole series 

 extends westward into Normandy, and it is interesting to 

 find an outlier of them in the Cotentin, due south of the 

 Isle of Wight ; the Oligocene beds are here only 36 feet 

 thick, but are believed by M. Dollfuss to include represen- 

 tatives of the whole Parisian series. 



In Belgium there appears to be a break and unconfor- 

 mity between the Eocene and Oligocene series, and the 

 latter present quite a different facies from the contempo- 

 raneous sediments of the Anglo-Parisian basin. They are 

 divisible into two groups only the Tongrien and the 

 Eupelien. The lower is about 100 feet thick, consisting 

 chiefly of sands with marine fossils, but including some 

 fluviatile beds. The higher (Rupelien) group is said to 

 overlap the lower beds and to contain fossils derived from 

 their erosion ; it consists of marine sands and clays, the 

 highest of which (Argile de Boom) is nearly 200 feet thick 

 at Eupel and somewhat resembles the London Clay. 



2. Geographical Restoration. 



Eocene Time. The gradual upheaval of the British 

 area, which took place at the close of the Cretaceous epoch, 

 continued until the greater part of our islands were raised 

 above the level of the sea, and they once more became part 

 of a continent which stretched far westward and south- 

 ward of their present limits. In imagining the aspect of 

 this land we must remember that a large part of it was the 

 upraised bottom of the Cretaceous ocean, and though, 

 doubtless, portions of the Chalk were removed by erosion 

 during upheaval, especially those which bordered the rising 



