Ch. xu.] climate of drift period. 145 



It appears clear, liowever, from wliat we know of the tertiary fossils oi 

 Europe — and I believe the same will hold true in North America — that 

 many species of testacea and some mammalia, which existed prior to the 

 glacial epoch, survived that era. As European examples among the warm- 

 blooded quadrupeds, the Eleplias primigenius and Rhinoceros tichorinus 

 may be mentioned. x\s to the shells, whether freshwater, terrestrial, or 

 marine, they need not be enumerated here, as allusion will be made to 

 them in the sequel, when the pHocene tertiary fossils of Suffolk are 

 described. The fact is important, as refuting the hypothesis that the 

 cold of the glacial period was so intense and universal as to annihilate 

 all living creatures throughout the globe. 



That the cold was greater for a time than it is now in certain parts of 

 Siberia, Europe, and North America, will not be disputed ; but, before 

 we can infer the universality of a colder climate, we must ascertain what 

 was the condition of other parts of the northern, and of the whole south- 

 ern, hemisphere at the time when the Scandinavian, British, and Alpine 

 erratics were transported into their present position. It must not be for- 

 gotten that a great deposit of drift and erratic blocks is now in full pro- 

 o'ress of formation in the southern hemisphere, in a zone corresponding 

 in latitude to the Baltic, and to Northern Italy, Switzei-land, France, and 

 England. Should the uneven bed of the southern ocean be hereafter 

 converted by upheaval into land, the hills and valleys will be strewed 

 over with transported fragments, some derived from the antarctic conti- 

 nent, others from islands covered with glaciers, like South Georgia, which 

 must now be centres of the dispersion of drift, although situated in 

 a latitude, agreeing with that of the Cumberland mountains in. Eng- 

 land. 



Not only are these operations going on between the 45th and 60th 

 parallels of latitude south of the line, while the corresponding zone ol 

 Europe is free from ice ; but, what is still more worthy of remark, we 

 find in the southern hemisphere itself, only 900 miles distant from South 

 Georgia, where the perpetual snow reaches to the sea-beach, lands covered 

 with forests, as in Terra del Fuego. There is here no difference of lati- 

 tude to account for the luxuriance of vegetation in one spot, and the 

 absolute want of it in the other ; but among other refrigerating causes 

 in South Georgia may be enumerated the countless icebergs which float 

 from the antarctic zone, and which chill, as they melt, the waters of the 

 ocean, and the surrounding air, which they fill with dense fogs. 



I have endeavored in the " Principles of Geology," chapters 7 and 8, 

 to point out the intimate connection of climate and the physical geogra- 

 phy of the globe, and the dependence of the mean annual temperature, 

 not only on the height of the dry land, but on its distribution in high 

 or low latitudes at particular epochs. If, for example, at certain periods 

 of the past, the antarctic land was less elevated and less extensive than 

 now, while that at the north pole was higher and more continuous, the 

 conditions of the northern and southern hemispheres might have been 

 the reverse of what we now witness in regard to climate, although the 



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