OF THE SEA AND LAND. 27 



that which was. I have no doubt that the chain 

 of Isla and Jura was once continuous; and stiU more 

 certainly was it so on each side of Scarba. It gives 

 passage to a tremendous tide : but that tide could no 

 more have existed before the breach was made, than 

 could a terrestrial current have assailed the side of a 

 wall of mountain and made a passage through it. 

 While that chain was one, the tide current, any current, 

 flowed between it and the land, as it was diverted by 

 that barrier; but it found some breach or fissure which 

 a stream had made, and forcing its way by degrees, it 

 produced Coryvrechan. It is but the river and the 

 ravine in another form: the tide sought the shortest 

 passage to restore the equlibrium, and the rest fol- 

 lowed. The very germ of the whole process may be 

 seen at Seil, where a bridge yet connects that island 

 with the main land. That passage will long be little 

 more than it is now; but when once the tide current 

 shall find a free opening here, the separation will pro- 

 ceed rapidly, and the geological posterity which never 

 heard of this bridge may agree that Seil was insulated 

 by Mr. Kirwan's currents, or by " The Deluge." It 

 is valuable to find such evidences of this tedious pro- 

 cedure as cannot be questioned, and they are much 

 oftener to be found than geologists discover. The 

 waste on the west side of Shetland is enormous; and 

 it would be easy enough to quote it as an instance 

 of the effect of oceanic currents or other brief violence- 

 Yet the Drongs, rising in slender pinnacles more than 

 a mile from the shore, and to the height of a hundred 

 feet, remain, a portion of that granite vein which can 

 be traced on the land, and marking the gentle and 

 slow efforts by which the including rocks were re- 

 moved. I trust that I may dismiss these imaginary 

 currents also; since I need not produce the thousand 



