time the climate became milder, the melting ice deposited 

 its boulder clay, and the high continent commenced to 

 sink again to its former level, during which gradual sub- 

 mergence the climate became still warmer, until it at 

 length reached a more than temperate mildness, at one 

 time being almost tropical. Still the land continued to 

 sink, and this submergence lasted until the British part 

 of the great continent had become a large archipelago of 

 small islands, the surface of the land being upwards of 

 one thousand feet below the present level. It has been 

 calculated that such a submergence would require at the 

 least 88,000 years to be completed ; so that a general 

 idea may be formed of the enormous periods of time 

 occupied by these glacial and inter-glacial epochs. While 

 the British archipelago existed, another change of 

 climate took place, resulting in another glacial period, 

 but probably not of such intensity as the previous 

 one. At this period the upper boulder clay was 

 deposited in the sea, to be afterwards upheaved above 

 the sea level in Yorkshire and other places. After a 

 long continuance of this glaciation the land commenced 

 to rise again and the climate to improve, until, after a 

 period of about 136,000 years (according to careful 

 computation), there was produced another continental 

 condition, the ground reaching about 600 feet higher than 

 now, and the climate becoming temperate once more. 

 England, Ireland, Scotland, Scandinavia, Denmark, the 

 Netherlands, France, and Spain once again formed a 

 mighty continent, the climate of which was cold-tempe- 

 rate, becoming milder year by year, and the elevation of 

 which was gradually declining, as it has continued to do 

 until the present time, the British islands slowly becoming 

 once more separated from the continent of Europe. 

 During the last temperate continental condition Palaeo- 

 lithic and Neolithic man lived in Britain, as is clearly 

 proved by the evidence brought forward by various 

 authors in support of the contention ; but, as we have 

 seen, Palaeolithic man's remains discovered in the various 

 deposits were often in the company of the bones of 

 extinct mammals belonging to a tropical fauna, which 

 species could not have existed in Britain with such a 

 climate as that which followed the last period of glacia- 



