CHAP. IX MILD ARCTIC CLIMATES 189 



by intervals of ancient glacial periods. The profiles I have 

 had the opportunity to examine during my various Spitz- 

 bergen 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 throughoat 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 somewhat less 

 tropical ; but down to the UpiDer 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 the Pliocene into the glacial epoch in Europe, 

 while in the Arctic zone there is a break in the record 

 between the Miocene and the recent glacial deposits.^ 



^ Geological Magazine, 1876, p. 266. In his recent work — Climate and 

 Cosmology (pp. 164, 172) — tlic late Dr. Croll has appealed to the imperfection 

 of the geological record as a reply to these arguments ; in this case, as it 

 appears to me, a very unsuccessful one. 



^ It is interesting to observe that the Cretaceous flora of the United 

 States (that of the Dakota group), indicates a somewhat cooler climate 

 than that of the following Eocene period. Mr. De Rauce (in the geological 

 appendix to Capt. Sir G. Nares's Narrative of a Voyage to the Polar Sea) 

 remarks as follows : " In the overlying American Eocenes occur types of 

 plants occurring in the European Miocenes and still living, proving the 

 truth of Professor Lesquereux's postulate, that the plant types appear in 

 America a stage in advance of their advent in Europe. These plants 

 point to a far higher mean temperature than those of the Dakota group, 

 to a dense atmosphere of vapour, and a luxuriance of ferns and palms." 

 This is very important as adding further proof to the view that the 



