. The earth and its inhabitants .. . merly resembled fine lines and groovings that mark the direction in which the ice sheets had 386 THE BEITISH ISLES. moved have been carefully mapped, and they show that the ice travelled outwardsfrom a great central snow-field which extended obliquely across the country,from the mountains of Connemara to the plateau of Antrim. To the northof this field of snow, which included the plateau of Magheraboy, with its hillsgrouped like the ribs of a fan, the groovings and striations are towards the north-west, whilst on the opposite slope their direc
. The earth and its inhabitants .. . merly resembled fine lines and groovings that mark the direction in which the ice sheets had 386 THE BEITISH ISLES. moved have been carefully mapped, and they show that the ice travelled outwardsfrom a great central snow-field which extended obliquely across the country,from the mountains of Connemara to the plateau of Antrim. To the northof this field of snow, which included the plateau of Magheraboy, with its hillsgrouped like the ribs of a fan, the groovings and striations are towards the north-west, whilst on the opposite slope their direction is south and south-west, exceptwhere the course of the ice was impeded or deflected by local mountain sheet of ice which at that period covered the plains of Ireland had a thicknessof 1,000 feet.* But long before the ice planed and levelled vast tracts of the surface of Ireland,the action of the water, operating through untold ages of our planet, had swept Fig. 195.—The Table-land of 1 : 200, 2 Miles. away a considerable portion of the surface strata. The plain which occupiesnearly the whole of the centre of the island is a proof of this. The extent of thisplain coincides pretty nearly with that of the carboniferous limestone, but thecoal measures of this formation have been removed, and there remain as itwere merely the foundations of the ancient edifices. Only here and there, inwell-sheltered localities, a few shreds of the coal-bearing strata which formerlyoverspread so large a portion of the island still exist. The agents of denuda-tion which deprived Ireland of her upper carboniferous strata were operative* Maxwell Close, Glaciation of Ireland ; Hull, Physical Geologj- and Geography of Ireland. IRELAND. 387 for many geological ages succeeding their deposition, during the whole of whichthe greater part of the island remained above the level of the sea. Evidenceof local depression, such as is afforded by ancient peat bogs lying below
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectgeography, bookyear18
