TOPOGRAPIIV AND GEOLOGY. 15 



ice slowly melted, these channels were recorded by 

 The Eskers. chains of gravel, the well-known " eskers," or " green- 



hills," which rise in wonderful freshness above the 



level of the plain. 

 The ice-age left the plain encumbered with glacial sands and gravels, and 

 the valleys in the mountains were often choked, like GlencuUen in Co. 

 Dublin, with similar materials, through which the streams now cut their 

 way. The abundant scratched blocks in these deposits show how the 

 stones were once pressed against one another, and were pushed into the 

 lowlands under the weight of solid ice. 



The Irish Channel, as we have seen above, was formed since the glacial 

 epoch, and was at one time even wider than it is at present. Clays were 



deposited on its shore, full of modern marine shells, 



f D If ^ which are now again lifted above the sea, and which 



Clays or Belfast, ^^j.^^^ ^q t^ke one instance, the foundations of Belfast. 



The sickle-shaped promontory of Larne, whence the 

 steamers start for Scotland, has been lifted some twenty feet since man 

 himself came into the countr}'. 



During these comparatively recent oscillations, now one way, now another, 

 the v.-hole western edge of Europe dipped sufficiently below the water to 

 allow the sea to flood the western valleys. These had long been occupied 

 by ice, and no debris could thus gather in their floors. They offered, as 

 the)" sank and as the glaciers melted, clean and clear inlets by which the sea 

 could penetrate the land. The fjords of Norway are the most notable 

 example, running in places lOO miles into the hills. Those of Scotland and 



Ireland originated in the same epoch of depression. 



The Western Hence one of the most delightful features of the west, 



Fjords. the narrow Killary Harbour (Fig. g), ten miles long 



and half-a-mile wide, is a true example of a fjord. 

 Uingle Bay, the Kenmare inlet, Bantry Bay, and many others, are also sub- 

 merged valleys ; it is hard to believe that we view the waters of the 

 Atlantic, lapping gently at high tide against the wild flowers on the shore. 

 Galway Bay and Clew Bay present the features of ordinary wide-mouthed 

 areas of submergence, such as are styled " rias " on the Spanish coast ; the 

 sharp northern edge of the former, running east and west, suggests a frac- 

 ture in the solid crust, with subsidence on its southern side. It is note- 

 Avorthy that this line, when continued eastward, coincides with one of the 

 lowest areas of the plain, the region between Galway town and Dublin. 



The lowering of the east coast, attendant on the separation of Ireland 

 from Britain, similarly produced rias or fjords. The Norse invaders saw m 

 them a reminder of their own indented coast, and the names of Waterford 

 and W'exford, Carlingford and Strangford, connect geology with history. 

 The north coast also has its submerged valleys, in the long inlets of Lough 

 Swilly and Lough Foyle. 



Ireland, then, as we know her, this land of crag and glen, of lake and 

 plain, owes the rich contrasts of her scenery to a long and complex series of 

 events. Yet the main structural lines of the country were impressed upon 

 it very early in its history. The Caledonian folding determined the heights 

 cf Donegal and the long backbone of Leinster ; the Hercynian folding 

 marked out the parallel ranges of the south, and, dying away to northward, 

 settled the broad reaches of the central plain. The Mournes and the Antrim 

 plateaux are the only recent features, and even they, somewhat proudly, can 

 claim precedence of the Alps. 



