OF LOCHABER. 



57 



even had some share in weakening the barrier dividing Loch 

 Roy from Loch Spean. 



The present depth of the Glen-mor-na-Albin, is more than 

 enough to have accounted for the escape of the waters of these 

 glens towards either sea ; it is, however, evident, that it has 

 been once much deeper, since the Caledonian Canal is now 

 cutting through great beds of alluvial, to which the debris of 

 the mountains brought down by torrents are every day add- 

 ing, so much so indeed, as to produce an evident diminution 

 in the extent of the higher lakes. And then Loch Ness itself 

 is so very deep ; — though I am rather disposed to think, that 

 the abyss containing it, may have been produced by some of 

 the last pangs of the convulsion, which perhaps operated with 

 greater violence there than elsewhere. A belief is very preva- 

 lent, that Scotland, to the northward of this glen, was once in- 

 sulated from the rest of the kingdom, by a narrow strait of the 

 sea running through it ; but from the circumstance of the ear- 

 ly disappearance of all marine exuviae, in the course of the cut 

 of the canal, from the sea, through the flat ground near Inver- 

 ness, this notion appears rather improbable. It would, how- 

 ever, be a highly interesting experiment, to bore for nearly 

 a hundred perpendicular feet, at some point about the sum- 

 mit-level of the Canal, in order to discover, what substances 

 would offer themselves. Some very curious geological specula- 

 tions might be awakened by such a trial, and some additional 

 and unexpected light might thus be thrown, upon the theory of 

 the ancient Lochaber lakes. It is very likely, that much evi- 

 dence bearing upon this last subject, might also be gleaned, by 

 extending our inquiries to the two extremities of the Glen- 

 mor-na-Albin, as well as to the appearances at the mouth of the 

 river Spey. The few investigations I have made as to these 

 points, have been much more superficial than I could have 



VOL. IX. p. I. H wished, 



