406 CONCLUSION. 



Geikie does not help us much, for his wording of changes 

 of level only refers to relative changes, for instance, " It is by 

 quiet, hardly perceptible movements, that the relative positions 

 of sea and land are undergoing change at the present time." 

 Lyell also speaks of the relative changes, and I cannot find a 

 passage to quote in which he speaks of anything but the 

 relative changes of level. Hoist (op. cit.) on the other hand, 

 I have already quoted as believing that a sea-saw motion 

 occurred between the north and south of the British Isles. 

 This author gives as a reason for this movement — the weight of 

 the ice on the Scotch land. Another writer, M. A. Marriott 

 in "Changes of Climate," says : " The glaciations themselves 

 seem to have caused differential movements in the earth's 

 crust owing to the enormous accumulations of ice over 

 certain areas." 



We then have reason to believe that the changes of level 

 were due to the (a) weight of ice lowering the land, and (b) 

 the enormous quantity of water locked up during the ice 

 bound period. It has been stated, but I am not able to quote 

 the author of the statement, that the ice reached a height of 

 over 4,000 feet over the enlarged arctic regions and that 

 locked-up water represented a fall of sea-level in the Atlantic 

 of nearly 1,000 feet. 



We have, therefore, enough ground to go upon to 

 formulate a theory that the raised beaches were the result of 

 the melting of the arctic ice, and that the submergences were 

 the result of the sinking of the land under ice weight. 



As this changed there would be a return to the normal 

 elevation, thus justifying my " points of stability." 



Dr. Hoist is of opinion that there has been but one 

 glacial period (op. cit. fol. 418). If he is right then I am 

 wrong. Geikie formulates no fewer than seven (Antiquity of 

 Man) if he is right I also am right. 



There is a way of explaining the difficulty. We may 

 consider the ice in the arctic regions to be there permanently 

 and the arctic circle to move up and down as the world 

 moves around its various axial centres causing warm and cold 

 periods. In this way a warm period follows a cold one and 

 all the phenomena of each is reproduced. 



A point of some importance is the fact that we have, as 

 far as my study goes, no evidence of any changes between the 

 rise of land after the deposition of the upper clay and the 

 submergence which buried the forests. We know that the 

 rise occurred because the forests grew, but the interval between 

 the second ice invasion and that of the forest elevation, but 



