PHYSICAL DESCRIPTION OF IRELAND xv 



which is enhanced by the fact that the prevaihng winds are westerly 

 and south-westerly. The genial effects of the ocean and the ocean 

 winds are most evident during the winter months. The winter 

 isotherms of Europe bend sharply north-westward as they leave 

 the continent ; Kerry has the same average temperature in Decem- 

 ber as Bordeaux and Rome. The reverse applies to summer 

 temperatures, when the cooling effect of the Atlantic is so great 

 that in July, Sligo is no warmer than Archangel. On the other 

 hand, the bitter easterly winds of spring which prevail in the 

 northern portions of the adjoining continent, and which are so 

 keenly felt on the east coast of Great Britain, reach Ireland 

 mitigated and softened, and have no appreciable effect on the 

 flora. While along the west coast of Ireland one has frequently 

 to travel some miles inland before even a shrub puts in an appear- 

 ance, and while all over the island the effect of the westerly winds 

 may be seen in the bending of the trees to the eastward, no such 

 result is noticeable as the effect of easterly winds, and in certain 

 spots on the east coast trees rise on the very edge of the sea. 



The westerly winds strike the shores of Ireland heavily laden 

 with moisture, which is precipitated, especially in the mountainous 

 regions. A rainfall of from 70 to 90 inches is recorded from certain 

 wet spots among the Kerry and Galway mountains. The average 

 rainfall of the west coast, though considerably less than these 

 figures, is still very high ; the precipitation decreases as we pass 

 eastward, and on the shores of the Irish Sea is no higher than on 

 the low grounds of western England. Roughly speaking, the rain- 

 fall west of the Shannon averages 40 to 60 inches, and east of the 

 Shannon 30 to 40 inches ; the mountain groups of both these areas 

 having a rainfall which exceeds the above figures. 



Rocks and Soils. — Ireland is formed mainly of Palaeozoic rocks. 

 The great projecting buttresses of the coast — the savage shores of 

 Donegal, "West Mayo, and West Galway, and the cliff- walls of North 

 Mayo, Clare, and Waterford, are formed of ancient slates and sand- 

 stones, quartzites and gneisses, and igneous rocks, of age varying 

 from Cambrian to Carboniferous. The splendid mountain-promon- 

 tories of Kerry and West Cork consist of slates and conglomerates 

 laid down in Devonian times, now folded into grand simple arches 

 and troughs. The high north-eastern corner of Ireland, with its 



