conditions. Turtles and crocodiles have left their remains behind 

 in the London Clay, and lieside the Odontopteryx already 

 mentioned there were herons, kingfishers, gulls, vultures, and 

 other large birds. All the species, however, are now extinct, and 

 there are no signs of man nor of any of the mammalia most nearly 

 related to him in structure. And Britain was not yet an island. 



During the next period, the (Jligocene, upheaval still went on, 

 more land was exposed, and a connection was made across the 

 Strait of Dover. All western Europe participated in this move- 

 ment, so that there was free communication with Africa in more 

 than one place. Across these pathways came multitudes of new 

 genera and species from the south ; Cornwall, Devon, and the 

 south-east of Ireland were mountainous districts with no separation 

 between them and France beyond the valley of a large river. The 

 greater part of the North Sea became dry, driving the waters 

 southward, but there was no connection with the Atlantic. During 

 this upheaval many lakes must have been left behind, and one 

 interesting set of lacustrine deposits has been preserved in Devon- 

 shire near Bovey Tracey. It appears to have been a lake at least 

 300 feet deep and covering about five and twenty square miles, fed 

 by the rivers Teign and Bovey, then qujte independent of each 

 other. Dartmoor stood there as now, but looking down on this 

 lake, whose waters reflected the forms of such trees as the 

 Sequoia, evergreen oaks, figs, cinnamon, laurels, vines, and gum- 

 trees, while large clusters of water lilies floated on the surface. 

 Everything betokened a warm climate. 



Still the elevatory movement continued, and through all the 

 Pliocene period. Great Britain aud Ireland appear to have remained 

 dry land, as no deposits of this age, or any signs of them are to be 

 found here ; we were still part of a largo continent, European on 

 the east, and stretching to Greenland and America on the west. 

 The North Sea formed a vast Miocene plain, watered by rivers from 

 the Scandinavian mountains, from Holland and Belgium, and on the 

 opposite ."^ide by those from Great Britain. There is at the present 

 time off the south-west coast of Norway a submarine valley 200 

 feet below the sea-bed ; possibly this is the valley of a large 

 Miocene river. The Miocene Age was a long one, as is shown by 

 the great changes which took place in the animals and plants. 

 Large areas of chalk and Eocene deposits were removed by the 

 rains, rivers and frosts of the time ; the great oolitic escarpment 

 stretching from the CotsAvold Hills to the N.E. was formed ; the 

 Thames commenced to carve out its present valley, though 

 probably only as a tributary of the Bhine ; and the dome of the 

 Weald was lifted up, and most of the chalk cleared off it. 



