Palcbontology. 339 



tween the Stonesfield slate and the eocene tertiary deposites ; 

 notwithstanding that there are indubitable proofs of the ex- 

 istence during that interval of extensive continents, of forests 

 growing on that land, of its being tenanted by other races of 

 animals, and that birds and pterodactyls spread out their 

 wings in the air above it. 



The land that supported the mammalia whose remains are 

 found in the eocene deposites of our island must have been sub- 

 merged, and must to a great extent have remained so during 

 the miocene period, when the adjoining continent was inha- 

 bited by the animals whose remains have been disinterred 

 there from the deposites of the miocene age ; for it is in plio- 

 cene and post-pliocene deposites that the mammalian remains 

 in the British Islands next present themselves. There is the 

 most conclusive proof that the animals lived and died, gene- 

 ration after generation, for a long succession of years, in the 

 land where their remains are now found ; evidence which 

 completely *' refutes the hypothesis of their having been borne 

 hither by a diluvial current, from regions of the earth where 

 the same genera of quadrupeds are now limited. The very 

 abundance of their fossil remains in our island is incompa- 

 tible with the notion of their forming its share of one genera- 

 tion of tropical beasts drowned and dispersed by a single ca- 

 tastrophe." 



The author ably discusses the question how the various 

 members of that ancient fauna came into this island. Other 

 and independent geological proofs shew that the British 

 Islands were united with the continent when it received its 

 pliocene mammalia, and the zoologist finds the known habits 

 and powers of these mammalia to be in accordance with that 

 configuration of the land. He then considers the no less im- 

 portant question, — although it is one more difficult of solu- 

 tion, — ^by what processes they became extinct? The sub- 

 terranean movements which separated our islands from the 

 continent, and submerged other parts of these islands, must 

 have produced such changes in the means of subsistence, and 

 powers of migration of these animals, as must have been one 

 great cause of their diminution and eventual extinction ; the 



