CAUSE OF MILD POLAR CLIMATES. 167 



given in ' Climate and Time,' probably includes the 

 greater part, if not the whole, of the Tertiary period. 

 He states that during the 2,400,000 years preceding 

 the last Glacial Epoch there were, according to the 

 table, no fewer than sixteen separate epochs when the 

 eccentricity reached or exceeded twice its present 

 amount. But it does not follow, according to the 

 physical theory, that there ought, on that account, to 

 have been sixteen epochs of more or less glaciation. 

 Whether such ought to have been the case or not 

 would depend on whether or not the geographical con- 

 ditions were the same during these epochs as they were 

 at the Glacial Epoch, a consideration with which the 

 theory has no relation. The question is not, were 

 there sixteen glacial epochs during the Tertiary period, 

 but were there any ? Even granted that those channels 

 assumed by Mr. Wallace did exist, they would not, I 

 feel assured, wholly prevent glaciation taking place at 

 the two periods to which reference has been made, 

 although the glaciation might not be severe. 



In support of the opinion that there is no evidence 

 of glaciation during the Tertiary period, Mr. Wallace 

 quotes the views of Mr. Searles V. Wood, Jun., on the 

 subject. Mr. Wood states that the Eocene formation 

 is complete in England, and is exposed in continuous 

 section along the north coast of the Isle of Wight and 

 along the northern coast of Kent from its base to the 

 Lower Bagshot Sand. It has, he says, been intersected 

 by cuttings in all directions and at all horizons, but 

 has not yielded a trace of anything indicating a cold 

 and glacial condition of things. The same, he adds, 

 holds true of the strata in France and Belgium. 

 Further, "the Oligocene of Northern Germany and 

 Belgium, and the Miocene of those countries and of 

 France, have also afforded a rich molluscan fauna, 



