308 SUMMARY OP GEOGRAPHICAL EVOLUTION. [CHAP. XIV. 



part of a high rocky and mountainous region which 

 stretched eastward across the area of the North Sea, but 

 the gradual detrition, planation, and burial of this ancient 

 land can be deciphered from the record of the Mesozoic 

 rocks, and does not constitute any difficulty in the way of 

 tracing the geographical evolution of Britain out of that 

 part of the Triassic continent which covered the British 

 area. 



It is conceivable that the progress of Geology may 

 enable some future student to restore the features and 

 outlines of the pre-Carboniferous land to the same extent 

 as we can now indicate those of the Triassic continent, and 

 by tracing the series of transformations which took place 

 in late Carboniferous and Permian times to describe the 

 processes which led to the growth of the great continents 

 that existed in the northern hemisphere at the beginning- 

 of Neozoic time. But even when this is done the Triassic 

 period will still form a new point of departure whence to- 

 follow the series of changes that occupied the long ages of 

 Neozoic time and culminated in the evolution of the 

 modern continents and oceans. 



With the Trias, in fact, we reach a stage in the geo- 

 logical history of Europe from which we can start with a> 

 reasonable expectation of being able to describe the gradual 

 building up of that Pliocene and Pleistocene continent out 

 of which the British Islands have been carved. Let us, 

 therefore, commence with a brief review of the geography 

 of the British region in Triassic time. 



The special features of the early Triassic land were the 

 broad plains and valleys which in the later part of the 

 period were converted into one long and branching lake- 

 basin, and which have left an impression on the physical 

 geography of Britain that has lasted to the present day. 

 The broadest of these plains lay over central England, and 

 was prolonged north-westward on the one hand through 



