SKI STAFFA. GEOLOGY. 



of water, whether that flow was gradual, or sudden, 

 without at the same time supposing a state of the surface 

 in which Staffa was continuous, at least with the neigh- 

 bouring island of Mull. If we imagine the origin of 

 the alluvial matter to be in that island only, it is sufficient 

 to prove the great changes which the surface must have 

 undergone since the period of this transportation. There 

 is scarcely any other method of explaining the present posi- 

 tion of this deposit but by supposing that the island of 

 Staffa had been protruded from below in its present form; 

 a 'supposition involving changes at least as great, and less 

 consistent with those revolutions of the globe which 

 seem most numerous and most strongly indicated. A 

 contemplation of the map will give the reader a notion 

 of the great waste of land which must have occurred 

 before the present separation of Staffa from Mull was 

 effected. Whether this loss of surface has resulted from 

 the violent or slow action of destroying forces, we have 

 no means of knowing. Yet perhaps the undisturbed state 

 of the trap strata, an argument which I have illustrated 

 at more length in speaking of Mull, tends to show that 

 this separation was not effected by dislocations, the 

 consequences of force exerted from below ; but that it 

 has been gradual and tranquil, or the result of powers 

 at least which have allowed the neighbouring parts to 

 remain in their original state.* 



* On that midsummer evening which terminated the preceding 

 observations on Staffa, the sun had set far toward the north, but 

 the red twilight was still shining at midnight on the grey mountains 

 of Mull and the walls of lona; its colour being reflected on a sea 

 that was tranquil as a mirror, and every object around in repose. 

 We had been busily employed from five in the morning, and, like 

 the sea birds that were floating by us on the silent water, the seamen 

 were sleeping on their oars. While the helmsman alone watched 

 for all, the idea of the present work first suggested itself to his mind. 

 If the reader shall derive instruction or entertainment from it, he 

 has not, for many perilous and busy months, and in seas of a far 

 different character, watched at the helm in vain. 



