DU NOTER— ON THE SOUTH OF lEELAND. 



243 



tions will be ^Yrougbt bj the sea at tlie surface, and by the earthquake 

 power beneath the crust of the globe, far beyond the most visionary 

 flights of imagination ever indulged in by the most accomplished 

 philosopher of nature. 



The last great geological event of which we can detect the traces 

 over the British Islands, w^as their gradual upheaval from beneath 

 the sea ; before that period, which comparatively speaking is a very 

 recent one, we know not how often our islands and Western Europe 

 had been submerged and elevated, or what were the outlines of the 

 land at these different post-Tertiary periods ; neither can we fix the 

 particular time when the Chalk of the South of England and the 

 North-west of France was cut through to form the Straits of Dover, 

 or the Basalt of the county of Antrim and the west coast of Scotland 

 divided by the Irish Channel. "VVe have however every reason to 

 believe that what are now the British Islands formed a portion 

 of the European Continent before the creation and distribution of 

 the existing Flora ; and doubtless during the lifetime of the 

 elephant, rhinoceros, hippopotamus, hyena, bear, etc., whose bones are 

 found in our caves as well as in those of the Continent. While from 

 recent discoveries it is possible that Man even may have been co- 

 existent with these now extinct animals. 



Tlie traces left by the sea during the period of the last upheaval 

 of the land, are generally understood by the term "Drift," and 

 they are such as to lead to the belief that ice floating over the 

 sea and glaciers forming in the mountain gorges were the chief 

 agencies of destruction, while the former, aided by tides and currents, 

 caused the transportation of rock masses over wide-spread areas. 



The presence of icebergs being once admitted, we must infer that 

 the temperature of the sea was much lower in these latitudes then 

 than now, and at the cessation of this period of upheaval the climatal 

 conditions must have closely approached to those of the Arctic zone ; 

 our mountain glens were occupied by glaciers for a very long period 

 indeed, as is proved by the extensive moraines now to be seen at their 

 mouths, and the grooving and polishing of the rocks along their sides. 



The last great current of the glacial sea certainly flowed from N. 

 and N.W. to S. and S.E. ; this is chiefly demonstrated by the occur- 

 rence of large boulders of peculiar rocks scattered on the surface to 

 the southwards of where they are recognized in situ. 



By studying the contour of the loftiest mountains in the South 

 of Ireland, such as Carrantuohill — the highest, 3414 feet above the 



