10 Anniversary Address of the 



three-fourths of its superficies), which is covered by water, 

 has undergone, in equal periods of time, oscillations of level 

 not inferior in degree to those to which the continental 

 spaces have been subjected. If therefore we were to 

 confine our thoughts to the mere outward modifications in 

 the shape of the land or bed of the sea, and all the changes 

 of climate and fluctuations in organic life inseparably con- 

 nected with movements which have amounted, in some cases, 

 to more than two miles vertically in one direction, besides 

 the lateral displacement of rocks and their denudation by 

 water, the series of events would seem endless, and their 

 magnitude not easily to be exaggerated. But it is evident 

 that these superficial mutations are trifling in amount in 

 comparison with revolutions which must have been going on 

 simultaneously in the inferior parts of the earth's crust. The 

 reality of these changes is certain, although their nature may 

 be obscure ; for we can rarely catch even a glimpse of the 

 subterranean products of the eocene, miocene, and pliocene 

 epochs, because it requires far more time than the tertiary 

 periods have as yet furnished, to allow the disturbing 

 causes to uplift, depress, and rend open, or for the ocean to 

 denude the incumbent rocks so as to make it possible for an 

 inhabitant of the surface to behold them and appreciate 

 their magnitude. 



The Alps indeed, where the convulsions have been greatest, 

 reveal to us some monuments of the vast chemical changes 

 and re-arrangement of the component elements of rocks 

 which have taken place since the deposition of the eocene 

 strata, and we thus gain some insight into the nature of the 

 transformation of mineral masses which must have been 

 going on contemporaneously at greater depths. It appears, 

 for example, that in some places granite has been intruded 

 into the axis of the Alpine chain, and that in other places 

 various granitiform compounds have been formed since the 

 whole nummulitic formation was elaborated beneath the sea. 

 " In passing," says Sir R. Murchison, " from east to west, 

 from the Austrian into the Savoy Alps, the zone of meta- 

 morphism widens laterally, from the centre to the flanks of 

 the chain, so as to afl'ect even the younger secondary deposits, 



