THE PHYSICAL EVIDENCE OF A SUBMERGENCE 65 



migrated on to the submerged land .surface ? This 

 would no doubt have taken place had the submergence 

 been of long duration ; but, short as the general 

 evidence leads us to suppose it to have been, such a 

 migration was not possible. The muddy state of the 

 waters would also for the time be a hindrance to 

 the existence of animal life. 



The physical evidence is to the effect that the 

 advancing waters had little erosive power, since they 

 failed to destroy the Beaches over which they passed, 

 or to wash away the dunes or blown sands which over- 

 lie the Eaised Beaches on the north coast of Devon 

 and Cornwall. At the same time, the advance of 

 the waters was progressive, as, had they been long 

 stayed, they would not only have destroyed these 

 surface features, but would have left their mark on 

 the land surface, either in the form of a beach, or by 

 a line of water-erosion on the rocks at the level at 

 which they remained for the time stationary. The 

 inference is that the waters rose slowly and con- 

 tinuously, charged merely with the mass of sediment 

 derived from the soil and rocks over which they 

 passed. This sediment, which was deposited either 

 at the high tide of the waters or at intervals as the}- 

 subsided, forms the mantle of Loess so conspicuous 

 in Central Europe, and of the slighter deposit of red 

 earth so widely spread on the lands bordering the 

 Mediterranean. 



That there was but a short lull when the sub- 

 mergence reached this stage is to be inferred from the 

 fact that the Bubble-drift rests immediately on the 



