Changes in Geography and Climate. 37 



degree affected the climate of Britain. Man first appeared 

 in Britain during the latter half of the Pleistocene Period ; 

 or rather we should perhaps say, that we have as yet no 

 satisfactory evidence of his earlier incoming. 



The physical geography of Britain during the period 

 which saw the formation of the Glacial and Palaeolithic 

 deposits is still uncertain in many points. I think, how- 

 ever, that the evidence warrants us in saying that no very 

 great changes affected the boundaries of land and sea. 

 Submergence of part of the land took place; but in the 

 South and East of England at any rate, only to a limited 

 extent, perhaps 1 50 feet. There was also a time when the 

 land stood at a greater elevation; though in England this 

 elevation above the present level does not appear to have 

 exceeded 70 feet. Coast-lines have also been cut back in 

 the course of time by the incessant action of the waves, 

 and in other places shingle-beaches or sand-dunes have 

 slightly encroached on the sea. But all these changes can 

 scarcely have been sufficient greatly to modify the outline 

 of Britain ; though in indirect ways their influence on the 

 flora must have been considerable. The changes which 

 modified the Pleistocene fauna and flora were of an 

 exceptional character; for, besides the enormous fall and 

 the great oscillations in the temperature, the accumulation 

 of vast uninhabitable deserts of ice and snow must have 

 blotted out all plant life over great part of Britain. These 

 deserts must also have affected the migration of the 

 Arctic plants in ways that even yet have been scarcely 

 recognised. 



An attempt will be made to give an outline of the 

 succession of events as far as the history can be traced ; 

 but it may be necessary to warn readers that I have been 

 led to interpret the records somewhat differently from other 

 geologists. Approaching the subject from the point of 



