TEKBACES AND RIVER VALLEYS OF WESTERN EUROPE. 285 



modern age ; in other words not earlier than the Middle 

 Tertiary period. It is generally recognised that the 

 physical features of the British Isles and Western Europe 

 received their more definitive form and outline during the 

 Mio-Phocene stages ; in the Alps, in post-Miocene times."^ 

 Though the general depression and partial submergence of 

 the existing lands in the Cretaceous period gave place to 

 considerable elevation accompanied by denudation at the 

 commencement of the Eocene period — it was not till after 

 the succeeding Miocene stage that the present sculpturing 

 of the features of the land was fully developed ; this 

 process was continued into the Pliocene and post-Pliocene 

 times. It was then that the hills, valleys, and river-channels 

 assumed the definite forms and arrangement, Avhich they 

 retain at the present day, and it was, consequently, during 

 this long-continued period that the submerged physical 

 features — the escaqDments and river-channels — continuous 

 with those of the land, received their definite outline and 

 direction. This observation applies especially to the south 

 and east of England where the more recent geological 

 formations are to be found. 



This view is in harmony with those arrived at by the 

 American observers of these phenomena along the eastern 

 coasts of America and the Antilles. Nor must the biolo- 

 gical evidence of recent continuity all round the submerged 

 platform, be overlooked. The flora of the south and west 

 of Ireland gives evidence of a former connection with that 

 of Spain and the south of Europe, as was long since pointed 

 out by the late Professor Edward Forbes, while the identity 

 of the fauna and flora of Iceland with that of [Scotland, 

 points to a similar land connection in very recent times, 

 notwithstanding the depression of 550 fathoms (3,300 feet), 

 by which the connecting platform is traversed; as shown by 

 the "Challenger " soundings. f The uprise in recent tijnes of 

 the bed of the North Atlantic to an extent of over 3,000 

 feet, is absolutely proved on biological grounds. Dr. 

 Wallace includes Iceland in his Palajarctic i^egion, which 

 embraces the British Isles and North Western Europe. 



* See sections across the Alps in various positions by Professors Albert 

 Heim, Carl Schmidt and H. Schardt in Livret-Gcide O'eologique^ dans Le 

 Jura et Les Alps de la Suisse, Lausanne (1894). 



t " Physical Chart of the world," " Challenger " Report, 1873-6 ; also, 

 Hudleston, " Eastern Margin of the North Atlantic Basin," Geological 

 Magazine, March, 1899 (Plate). 



