Britain was then continuous with the Continent of Europe, so 

 that there was no impediiuent to the migration of animals and 

 plants. 



After tlie Miocene came the "Pliocene" period, during whicli 

 the animals much resemhled those of the present day. 



Over the area which is now knoAvn as Great Britain and 

 Irelanil, tlie change wrought by the action of ice took place. In 

 the course of centuries, the climate of Britain became colder and 

 colder, and the severest stage of glaciation set in. With this 

 decrease of temperature the polar ice-cap came down to lower and 

 lower latitudes, and the conditions which are found in Greenland 

 to-day, prevailed hi the Britain of that day. Snow falling on 

 several centres served to feed the glaciers, and the great glacier 

 system of Scandinavia came down to the British glaciers, and 

 determined their course northward and southward. Before the 

 polar ice-cap descended there was rich vegetation in Britain — pine, 

 oak, and l)eech forests abounded — but glaciers 2000 or 3000 feet 

 thick ploughed up everything before them, and the forests of 

 Pliocene Britain were utterly destroyed. All the animals were 

 driven out and went southward. 



A good example of the results of this glacial action is to be 

 seen in the Pass of Llanberis, in Xorth Wales. Here are found, 

 perched high up on the valley, rocks which are of a different com- 

 position from those in the neighbourhood, and which must have 

 been carried from a considerable distance. Some of them weigh 

 as much as 2000 tons, and they remain beliind as permanent 

 memorials of a huge glacier which has long ago melted and 

 evaporated. 



At one time the land of Britain was at a considerable elevation 

 above the sea level, and extended to some distance into the 

 Atlantic. Next came a time ^\•hen the land slowly sank, and only 

 a few projecting portions remained above the water. Britain then 

 presented the ajipearance of an archipelago. The greater portion 

 of Eastern England was submerged. At this time glaciers passed 

 among the islets, and each breaking off at its free extremity, formed 

 "ice-bergs,"' which dropped their burden of clay and boulders on 

 the sea-bed below. The ice at length slowly disappeared, and then 



