HO DISCUSSIONS IN CLIMATOLOGY. 



some places leave its mark in the form of a terrace or 

 a raised beach ; but no doubt, such cases would be 

 exceptional. The condition of things becomes further 

 complicated by another cause referred to in ' Climate 

 and Time ' (p. 388), which will occasionally come into 

 operation ; viz., a lowering of the general level of the 

 ocean resulting from the abstraction of the ice, or a 

 rise resulting from a general decrease of the ice. 



The submergences and emergences arising from dis- 

 placement of the earth's centre of gravity would of 

 course leave evidence of their existence in the form of 

 stratified deposits ; but, as we have already seen, no 

 one could possibly determine from such deposits the 

 number of elevations or depressions of sea level which 

 actually took place. 



I think it is probable, however, that some of the 

 more recent well-marked changes of sea level, such as 

 those indicated by the Carse-clays and the submarine 

 Forest-beds, were due to displacements of the earth's 

 centre of gravity. I am inclined also to believe that 

 the rise of the land, or rather the lowering of the sea 

 level during the interglacial or continental periods, in 

 many cases, resulted from the same cause. If we admit, 

 with some geologists, that the sinking of the land was 

 due to the weight of the ice, we shall have an explana- 

 tion of glacial submergences ; but such a theory will 

 in no wise explain the elevation of the land during the 

 continental periods. It is true, the removal of the ice 

 might allow the land to regain its former level ; but 

 its removal could have no tendency to raise the land 

 above that level. 



The whole matter of glacial submergence is too 

 obscure and complicated an affair to allow us to 

 determine, with anything like certainty, how often 

 the land might have been under water during the 

 glacial epoch. 



