14 TOPOGRAPHY AND GEOLOGY 



London Clay and other marine deposits were quietly accumulating in the 

 south of England. Hence, the volcanoes of Antrim are of Eocene age, and 

 and may have extended into the next period, the Oligocene. They were the 

 forerunners of tremendous changes in the physical geography of Europe. 



For, soon after the Irish outbreak, the ridges of the Pyrenees and the 

 Juras appeared above the level of the sea ; the Alps themselves followed, 

 and the great Carpathian ring, accompanied by volcanic eruptions of their 

 own. The Balkans, the Caucasus, the Himalayas, date from the same epoch 

 of unrest ; and the disturbances in the Scotch and Irish areas, on the edge 

 of the old northern continent, may be said to mark the opening of the 

 Alpine movements, which have built up the continents of to-day. 



Moreover, the cessation of eruption in Ireland was accompanied by the 

 breaking up of the northern land. The lava-plateaux cracked and sub- 

 sided, and, as Sir Archibald Geikie shows us, now He in great part on the 

 floor of the north-east Atlantic. The basin of Lough Neagh was produced 

 by a settlement of this kind, while the basalt on either hand remained high 

 on the hills of Antrim and Sheve Gallion. The edge of Europe was now 

 in process of formation ; Ireland vv^as, as it were, detached on the north and 

 west from its ancient allegiance, and was tacked on to the new continent, 

 still in its birth-throes, on the east. 



Even now, Ireland was not an Island. Through Miocene and Pliocene 

 times it remained an integral part of Europe. Animals found their way 

 into it which could not have swum or flown across the sea, but which neces- 

 sarily wandered in upon dry land. Considering the antiquity of its own 

 land-surface, Ireland may have nourished some forms of mammalian life 

 before they could gain a foothold in Europe ; but the strange epoch of cold 

 in the northern hemisphere, known as the Ice-age, probably drove most of 

 them eastward and southward. When they returned, in happier times, 

 they still entered the Irish area on dry land. But a gradual subsidence was 

 taking place, and Ireland was at last converted into an island on the Euro- 

 pean edge. Mammals continued to enter England, whereby the fauna of 

 that country became richer than that of Ireland. In turn, by marine exca- 

 vation, as well as by subsidence, Britain was cut off also, by the formation 

 of the Straits of Dover and the shallow North Sea basin, and its fauna 

 remains, therefore, limited in comparison with that of continental Europe. 



During the Ice-age, or the Glacial epoch, the mountain-rim of Ireland 



was probably far higher than it is now. The glaciers 



The Glacial that gathered on it have everywhere scored the sur- 



Epoch. face of the rocks. The lower grounds of Kerry and 



Connemara, and even some thousands of feet of 



barren mountain-wall, have been moulded into the smooth round forms 



that are known as roches nwutonnces, from their resemblance to the mammil- 



lations of a lawyer's wig (Fig. 8). Between Kenmare and Glengariff, these 



features are fully as evident as in the classic region of North Wales. Snow, 



compressed into a huge flat glacier, accumulated in the basin of the plain, 



which, as we have seen, was first marked out by the antique Hercynian 



folding, and which now served as the receptacle for all the debris of the 



mountains. The glaciers brought down, especially in their lower layers, 



abundant blocks and pebbles picked up in their passage from the hills ; the 



streams running under the broad ice-sheet of the lowlands washed these 



materials along their courses, and piled them up in their groove-like channels 



under the ice. When at last the temperate climate was restored, and the 



