K£ VIEWS. 



260 



far-famed Lakes of Killarney. On approaching this region from the east, it is 

 impossible not to be struck with the vast accumulation of detritus, with large 

 boulders derived from the rocks of which the mountains are composed. This 

 deposit of the age of the northern drift is spread over the low-lying district of 

 Carboniferous limestone which extends to the lower lake. On the western and 

 southern sides of this lake the mountains rise abruptly and attain at Carn Tual 

 an elevation of three thousand four hundred and four feet, and here the glacial 

 phenomena are as strongly pronounced as in any part of Wales and Scotland. The 

 Black Yalley, one of the most wild and striking, which stretches from the head of 

 the lower lake to the base of Macgilly cuddy's Reeks, exhibits these appearances 

 in their most marked form. The surfaces of the rocks are here worn into smooth 

 oval bosses, lying with their major axes in the direction of the valley, and ex- 

 tending several hundred feet up the sides. These polished roches moutonnees, 

 however, assume a singular appearance when traced into the upper lake. They 

 rise above the surface in the form of small oval islands, lying parallel to each 

 other, and, though frequently clothed with luxuriant vegetation, are generally 

 smooth and bare. It is impossible to give an idea of these ice-moulded bosses, 

 protruding their naked backs above the calm waters of the lake, bearing some 

 resemblance to a number of up-turned hulls of ships, or to a shoal of whales 

 swimming half out of the water." 



Nearly all the main valleys present similar appearances. The rocks, wherever 

 freshly exposed, are grooved and striated : the picturesque valley of Glengariff 

 being specially remarkable for the freshness of the ice-groovings and scratches. 

 These striae point west-south-west, stretching along the valley till it is sub- 

 merged in the sea at Bantry Bay. 



The years 1S41-42 appear to have been remarkably prolific in researches inlo 

 the glacial phenomena of our islands, for we find Professor Agassiz, Dr. Buck- 

 land, and Sir C. Lyell announcing consecutively their convictions of the former 

 existence of a state of things in these islands, which have their aualogues only 

 in Greenland, South Georgia, or Tierra del Fuego, at the present day. M. 

 Agassiz pointed to the Caernarvonshire mountains as one of the centres of dis- 

 persion of glacial and erratic detritus ; and Dr. Buckland speedily followed 

 with details tending to prove that the seven valleys of Snowdonia were once 

 occupied by as many glaciers, discharging loads of boulders and gravel over the 

 lower grounds or into the sea, and covering the bottoms and sides of those 

 valleys with flirtings and furrows. He also shows that on the northern flanks 

 of this district, boulders and marine drift coming from Anglesea, Cumberland, 

 or Ireland, and containing, as shown by Mr. Trimmer, marine shells, have been 

 deposited at an elevation of one thousand three hundred and ninety-two feet on 

 MoelTryfane. 



The observations of Dr. Buckland were followed by those of Mr. Darwin, 

 and more recently by those of Professor A. C. Ramsay. This author has shown 

 that many of the tarns, such as Llyn Llydaw and Lly'n Idwal, have been pro- 

 duced partly through the damming up of the waters by moraines, as Agassiz 

 had previously shown to be the case in the Alps, and Lyell in Forfarshire. The 

 same author, in order to account for the fact that several of the mountain tarns, 

 as those near the summit of Cader Idris, Moel Wynne and Snowdon, are in the 

 form of basins hollowed out in solid rock, has suggested an explanation which may 

 be called " the scooping theory." These tarns are generally surrounded through 

 half their cireumferance by precipitous walls of rock ; and Professor Ramsay 

 supposes that solid masses of ice, descending from these heights, charged with 

 imbedded fragments of rock, have actually scooped these hollows, which are so 

 numerous in all mountain districts. 



But there is one interesting fact brought out by Professor Ramsay, and 

 which, according to my own observation, is repeated amongst the valleys of the 



