326 MAN AND THE GLACIAL PERIOD. 



that the subsidence was greatest at a time when the press- 

 ure had already begun to diminish. But the fact that 

 the land, after the removal of the ice-load, did not return 

 again to its former height in the Pliocene, is proof posi- 

 tive that there were other and more fundamental causes 

 of crust-movement at work besides weighting and light- 

 ening. The land did not again return to its former level 

 because the cycle of elevation, whatever its cause, which 

 commenced in the Pliocene and culminated in the early 

 Quaternary, had exhausted itself. If it had not been for 

 the ice-load interfering with and modifying the natural 

 course of the crust-movement determined previously and 

 primarily by other and probably internal causes, the lat- 

 ter would probably have taken the course represented by 

 the dotted line. It would have risen higher and culmi- 

 nated later, and its curve would have been of simpler 

 form. 



We append a carefully prepared table by Mr. Warren 

 TJpham, showing the probable changes in altitude and 

 climate during the Quaternary era. * 



On the part of many the theory here provisionally 

 adopted will be regarded with disfavour by reason of a dis- 

 inclination to supposing any great recent changes of level 

 in the continental areas. So firmly established do the 

 continents appear to be, that it seems like invoking an 

 inordinate display of power to have them exalted for the 

 sake of producing a Glacial period. Due reflection, how- 

 ever, will make it evident that within certain limits the 

 continents are exceedingly unstable, and that they have 

 displayed this instability to as great an extent in recent 



* On page 106 and sequel I have summarised the reasons which 

 lead me to discard the Inter-Glacial epoch, and to look upon the 

 whole Glacial period as constituting a grand unity with minor 

 episodes. It does not yet seem to me that the duality of the period 

 is proved. On the contrary, Mr. Kendall's chapter on the Glacial 

 phenomena of Great Britain strongly confirms my view. 



