182 



ISLAND LIFE. 



[part I. 



repeated alternation of warm and glacial climates between the 

 present time and the earliest geological ages."^ And again, in 

 his Sketch of the Geology of Spitzhergen, after describing the 

 various formations down to the Miocene, he says : "All the 

 fossils found in the foregoing strata show that Spitzbergen, dur- 

 ing former geological ages, enjoyed a magnificent climate, which 

 indeed was somewhat colder during the Miocene period, but 

 was still favourable for an extraordinarily abundant vegetation, 

 much more luxuriant than that which now occurs even in 

 the southern part of Scandinavia ; and I have in these strata 

 sought in vain for any sign, that, as some geologists have of late 

 endeavoured to render probable, these favourable climatic con- 

 ditions have been broken off by intervals of ancient glacial 

 periods. The profiles I have had the opportunity to examine 

 during my various Spitzbergen expeditions would certainly, if 

 laid down on a line, occupy an extent of a thousand English 

 miles; and if any former glacial period had existed in this 

 region, there ought to have been some trace to be observed of 

 erratic blocks, or other formations which distinguish glacial 

 action. But this has not been the case. In the strata, whose 

 length I have reckoned alone, I have not found a single 

 fragment of a foreign rock so large as a child's head."^ 



Now it is quite impossible to ignore or evade the force of 

 this testimony as to the continuous warm climates of the north 

 temperate and polar zones throughout Tertiary times. The 

 evidence extends over a vast area, both in space and time, 

 it is derived from the work of the most competent living 

 geologists, and it is absolutely consistent in its general tendency. 

 We have in the Lower Cretaceous period an almost tropical 

 climate in France and England, a somewhat lower temperature 

 in the United States, and a mild insular climate in the Arctic 

 regions. In each successive period the climate becomes some- 

 what less tropical ; but down to the Upper Miocene it remains 

 warm temperate in Central Europe, and cold temperate within 

 the polar area, with not a trace of any intervening periods of 

 Arctic cold. It then gradually cools down and merges through 



^ Geological Magazine, 1875, p. 531. 

 ^ Geological Magazine, 1876, p. 266. 



