CHAP, ii.] THE EOCENE SEA. 19 



According to the observations of Mr. Sorby 1 on the 

 marine currents, the sea in which the Post-nummulitic 

 rocks of the Isle of Wight were deposited was shut off 

 from the Atlantic by a barrier of land running due south 

 from Dorset, Devon, and Cornwall, towards Normandy 

 and Brittany, the main body of the ocean being to the 

 east or south-east, and extending at least as far to the 

 north as Denmark. 



This sea teemed with life of various kinds, now to be 

 found, for the most part, in the warmer regions of the 

 ocean. Gigantic sharks, rays, sword-fishes, and sturgeons, 

 and the peculiar armour-clad fish the Lepidosteus, found 

 their prey in vast abundance. There were turtles also 

 innumerable, and sea-snakes, some of which (Palceophis) 

 were twelve feet long. Among the more important 

 mollusca we may notice the nautilus, the cone, volute, 

 cowrie, olive, and large spindle shells (Fusus), which 

 belong to the marine fauna of the tropics. 



The Eocene lakes, rivers, and seas were singularly 

 rich in reptilian life. " More true turtles," writes Pro- 

 fessor Owen, 2 " have left their remains in the London 

 Clay, at the mouth of the Thames, than are now known 

 to exist in the whole world ; one (Chelone gigas) is of 

 enormous size, with a head upwards of a yard across. 

 Emys and Platemys haunted the rivers, while the estu- 

 aries were the feeding- places of the soft turtles (Trionyx), 

 and basking on the shores were to be seen crocodiles, 

 alligators, and the long-snouted gavial, now only living 

 in the rivers of India." 



1 " Physical Geography of the Tertiary Estuary of the Isle of Wight," 

 by H. C. Sorby, Esq. Edinb. New Phil. Jour. N.S. April 1857. 



2 Owen, Pafaontology, p. 281. 



