1889.] THE DISPLACEMENT OP BEACH-LINES. 39 



with the interior heat of the earth. The Glacial age stood 

 as an interruption in the continuity of this steady cooling pro- 

 cess. In the times of transgression, when the land lay low, and 

 the seas were widely distributed in northern latitudes, the warm 

 ocean currents had much easier access to the Poles tb n 11 the 

 dry-land or continental periods. As we, however, are best 

 acquainted with the beds formed in the times of transgression, 

 and as the beds of the continental periods are, for the greater 

 part, destroyed by denudation and, partly, are concealed by the 

 waters; it is reasonable enough that the beds of the ancient 

 cycles must show less distinct geographical provinces, and, as a 

 rule, testify to milder climate, even in high latitudes. But the 

 great alterations in the division of land and sea have compelled 

 us to assume that, step by step, with these alterations, a periodi- 

 cal alteration of climate has also taken place, which has been 

 far greater and more radical thau the alteration produced by the 

 period of precession. 



Ramsay, Croll, J. Geihie and others have supposed that 



the ancient formations (vide e. g. J. GeiJcie: The Great Ice 

 Age. Ed. 2. London 1877, Appendix p. 566 ff.). 



Some of these traces appear to prove that at all events 

 there must have been several other glacial ages than the post- 

 tertiary. But v. Bichthofen (Fiihrer fur Forschungsreiseude, p. 

 362) states that those presumable traces of glacial epochs are 

 perhaps only an abrasional phenomenon, that the beating of the 

 waves on the shore might form conglomerates with striated 

 stones. Whatever the real facts may be in regard to some of 

 those presumable ancient glacial ages, the most distinct and certain 

 traces (cfr. J. Gertie 1. c.) are seen to be obtained in the Devon- 

 ian sandstone „01d Red" of England and Scotland; from the 

 commencement of the Carboniferous period (Scotland); from 

 Permian conglomerate (England ; from the Eocene epoch (Switzer- 

 land). The most speaking evidence (with striated stones) is 

 obtained from the periods when the land was widely dis- 



