592 SCIENTIFIC RECREATIONS. 



were even mixed up, and almost fabulous creatures inhabited the land where 

 England now is. We read of antelope-horses, lion-like bears, and camel- 

 stags. The vegetation was then of a tropical kind, and in the deep forests 

 and jungles these enormous animals the mammoth dinotherium, and such 

 species roamed and plunged in the swamps at the mouth of the Thames. 

 At length these types died away, and gave place to the elephant and the 

 hippopotamus, and the climate by degrees became less warm, and still slowly 

 decreased in temperature. 



A glance at Sir C. Lyell's " Principles of Geology" will show us how, 

 as we examine the more modern strata, we find a great increase in the 

 European lands, which may have been compensated by the submersion of 

 the Pacific islands. During the period of the vegetation of the Secondary 

 epochs, our climate (between the lias and the chalk) was favourable to a 

 tropical growth. Enormous rivers flowed through our islands, and gigantic 



Fig. 681. Section across the London Basin (W. Whitaker). 



a Lower Bagshot sand (of Hampstead). b London Clay, c Reading and Woolwich beds (including the Oldhaven beds, 

 which occur in the south only), d Thanet sand (crops out on the south only), e Chalk with flints, f Chalk without flints. 

 g Upper Greensand (crops out on the south only), h. Gault. i Lower Greensand. k Wealden beds (on the south only). 

 / Oolitic clays (shown only on the north, but proved to occur on the south beyond the range of the section, by the sub- 

 Wealden boring, near Battle, in Sussex). X Old rocks, shown by borings at Kentish Town and at Meux's Brewery, to pass 

 under the London basin. 



crocodiles, etc., with flying reptiles, were masters of the land. There were 

 numerous fishes, but the reptiles did not appear in such very great numbers. 



These large and elephantine animals must have existed while the 

 climate of Northern Europe underwent some very considerable changes. We 

 read of the woolly rhinoceros, and the hairy elephant, or mastodon, which 

 has been found in Siberia. Reindeer appeared in England, and we know 

 now that these animals inhabit cold countries. The mountains were con- 

 siderably elevated during the latter Tertiary period ; snow fell and ice 

 formed upon the summits of the mountains, while glaciers crept down the 

 sides. The warm, almost tropical climate of the prior ages was gradually 

 but surely giving way to the Ice Age ; the earth was slowly dipping, and the 

 sun's rays had less power. 



-Professor Ramsay says the " assemblage of fossils found in the London 

 clay point to the fact that the whole of these strata were deposited in the 

 estuary of a great continental river comparable to the Amazon and the 

 Ganges. The palm-nuts and the host of other plants help to prove it, and 

 the remains of river tortoises, crocodiles, snakes, marsupials, and several 

 tapir-like mammals, all point in the same direction. The estuarine con- 

 ditions begun during the deposit of the Woolwich and Reading beds were 

 still going on when the London clay was thrown down ; with this difference, 



