250 THE ENTOMOLOGIST. 



and the huge perched blocks of stone near the Devil's Punch 

 Bowl Lake, 2319 feet above the sea, appear only explicable 

 on the supposition of long and deep submersion ; but the 

 grooving and polishing of rock-surfaces, so conspicuous on 

 the low grounds at Killarney, the striae always being in the 

 direction of the longest axis of the valley, and especially the 

 forms of the islands in the upper lake, with their noses, so to 

 say, all pointing in the same direction as the striaj, seem 

 best explained by the action of land ice moving over the 

 surface of the upraised bed of the glacial sea, and Professor 

 Tyndall takes this view : I extract the follow ing passage 

 from liis work, ' Heat Considered as a Mode of Motion :' — 

 " On the south-west coast of Ireland rise the Reeks of Mac- 

 gillicuddy, which tilt upwards, and catch upon tlieir cold 

 crests the moist winds of the Atlantic ; precipitation is 

 copious, and rain at Killarney seems the order of Nature. 

 In this moist region every crag is covered with rich vege- 

 tation, but the vapours, which now descend in mild and fer- 

 tilizing rain, once fell as snow, which formed the material for 

 noble glaciers. The Black Valley was once filled with ice, 

 which planed down the sides of the Purple Mountain as it 

 moved towards the upper lake. The ground occupied by 

 this ]al<e was entirely held by the ancient ice, and every 

 island that now emerges from its surface is a glacial dome. 

 The fantastic names which many of the rocks have received 

 are suggested by the shapes into which they have been 

 sculptured by the mighty muulding-plane which once passed 

 over them. Where the barren rock has been exposed for 

 ages to the action of the weather the finer marks have in 

 most cases disappeared, and the niamillated forms of the 

 rocks are the only evidences ; but the removal of the soil 

 which has protected them often discloses rock-surfaces, 

 which are scarred as sharply and polished as clearly as those 

 which are now being scratched and polished by the glaciers 

 of the Alps." 



Alter passing the narrow gorge between the precipices of 

 Cromaghlan and the Eagle's Nest, which form the portals to 

 the basin of the upper lake, the valley expands, and, joined 

 by another glacitr descending on the east from Mangerton, 

 the combined mass of ice probably filled, if it did not 

 actually excavate, the basin which contains the middle and 

 lower lakes. 



