266 [Proc. B. N. F. C, 



Ireland to-morrow would be, it would appear as if an even 

 greater interval had elapsed. Originally spread out in vast 

 continuous sheets, their present contours are not due to disloca- 

 tions or upheavals which have thrown them into mountainous 

 shapes, but their mountains have been carved out of the solid, 

 inch by inch, by the slow process of weathering, which has cut 

 down through them to a depth of 2000 feet. In this country 

 the basaltic region still presents a plateau-like aspect, but in 

 Iceland, the plateaux, where not concealed by ice or recent 

 volcanic products, are cut up into long rolling hills 1000 to 

 2000 feet in height, separated by wide, nearly parallel valleys, 

 the flanks of the hills, where still exposed, being slowly disinte- 

 grated, or buried under their own debris. The denudation is 

 colossal, and solitary pinnacles or protuberances everywhere 

 attest, like monuments, the former presence of sheets of basalt 

 of which no other trace remains. The Faroes are even more 

 eloquent of waste. This little group of some 20 islands and 

 islets, presents the ruins of a once continuous plateau 2000 or 

 more feet in height. The hills, as in Iceland, are usually flat- 

 topped like Sleamish, but the cliffs, frequently 1000, and some- 

 times 2000 feet in height, are almost vertical, and fretted, espe- 

 cially on their Western faces, into weird and fantastic forms. 

 The sub-aerial waste is here supplemented by the attacks of the 

 waves, and the sea-bed for miles around is shallowed by the re- 

 deposited silt. In Scotland only disconnected fragments of the 

 erupted matter remain. " Some of the noblest hills of the 

 Inner Hebrides are but solitary outliers left standing amid the 

 ruins of the great sheets of solid rock of which they once formed 

 a part. Ben More, in Mull, though more than 3000 feet high, 

 is only a magnificent fragment of the larger pile of volcanic 

 material which formerly swept over what are now the deep 

 glens and fjords of Mull. The long lines of imposing cliff with 

 which the basalt plateaux front the Atlantic all through these 

 islands, from the Fair Head of Antrim to the far headlands of 

 Skye, tell everywhere the same tale of vast and continuous 

 denudation."* " But most striking of all is this fact of enormous 



*Geikie, J^uart. Journ. Geol. Soc, vol. xxvii., p. 285. 



