394 THE BRITISU ISLES. 



the greatest contrast to the uniform development of the cast coast. On that side 

 of IrcLind there arc but two ishmds, Lanibay Island and Ireland's Eye, near 

 Dublin Bay, besides the banks which mark the former extent of the coast, and 

 terminate with the Tuskar Rock in the south. 



The reasons for this contrast must be looked for in glacial action ; for Western 

 Ireland, which is exposed to the moisture-laden winds of the Atlantic, remained 

 much longer buried beneath a sheet of ice and snow than the east, where the dry 

 winds blowing from the continent exercised more influence. But other agencies 

 have no doubt aided in the formation of these western firths. The elongated bays 

 of Kerry, for instance, so remarkable for their parallelism, appear to have been 

 scooped out by the chemical action of the waves, which dissolved the calcareous 

 rocks of the valleys, but respected the old red sandstone forming the promontories. 

 This chemical action is analogous to that which continually enlarges the lakes of 

 the central plain. In several instances these Irish firths, like those of Scotland, 

 terminate in lakes, as in the case of Ballinskelligs Bay, near the south-westernmost 

 promontorv of Kerry, at the head of which lies Lough Currane. In the same 

 county of Kerry we meet with rocks which become calcined through the action of 

 the sea. The cliffs of Ballybunion, which rise in crags and needles to a height of 

 ] 50 feet, are perforated by caverns at their foot. They enclose beds of bitumen 

 and deposits of pyrites, which a landslip occasionally exposes to the action of the 

 atmosphere. Whenever this happens the pyrites decompose spontaneously with a 

 considerable evolution of heat, sufficient to set fire to the bituminous rocks, and 

 whilst the foot of the cliffs is then lashed by the waves, columns of smoke may be 

 seen curling up from its summit.* 



The climate of Ireland is essentiall}^ a maritime one, and even more humid 

 than that of Great Britain. The rainfall throughout the island averages 

 36 inches, and in the hills, which condense the moisture of the prevalent westerly 

 winds, the amount of precipitation is more considerable still. No other country 

 of Europe is so abundantly supplied with rain. Occasionally the downpour along 

 the western coasts is so considerable that the sea, for a great distance from 

 the land, becomes covered with a thick layer of fresh water. The fishermen drink 

 this water, and naturalists may witness the curious spectacle of two superposed 

 faunas — the one fluviatile, the other marine. The marine animals, on being brought 

 into the surface water, become paralyzed, whilst the fluviatile ones are poisoned on 

 being plunged into deep water. f Westerly and south-westerly winds prevail, and 

 they are frequently of great violence. The American cyclones, in their progress 

 to Europe, always pass over Ireland. Even the Irish Sea is exceptionally tem- 

 pestuous, owing to these south-westerly winds and the conflicting tidal waves which 

 meet within it. 



The extreme humidity of the climate exercises a retarding influence upon the 

 harvest. ^Vheat is never cut before the beginning of September, and in excep- 



♦ William Ainsworth, " Caves of Ballybunion," 1834. 



t Edward Forbes, " Natural History of the European Seas." 



