On the Shelves of Lochaber. 7 



possibility of clearing the country of the assumed mass of 

 detritus, so as to give its present aspect, by the means which 

 nature has furnished. Supposing that such a mass had existed, 

 it may be asked, what has become of it ? Have the streams 

 of the district such power as to warrant the idea that they 

 carried it back to the region Avhence it was brought % I can- 

 not think that any one who has seen them, even in a state of 

 flood, will answer in the affirmative. 



I now proceed to state what I have long entertained as the 

 most probable cause of the production of the shelves. 



It is now admitted, I may say almost universally, that the 

 evidence of water having flowed over the land, and in this 

 country in a direction from between west and north to be- 

 tween east and south, is complete. As we find detritus de- 

 posited at fully 1500 feet above the sea, the water which 

 carried it must have had its surface greatly more elevated. 

 Some suppose, as Mr Milne, that this deposition took place 

 while the surface was under the ocean. The permanency and 

 parallelism of the Lochaber shelves, together with all the phe- 

 nomena of the diluvium or drift, including the absence of 

 marine exuviae from the latter, persuade me irresistibly^ 

 that when they were formed, the land had acquired its pre- 

 sent general relative position to the level of the sea ; admit- 

 ting, nevertheless, that partial and local, though not exten- 

 sive, gradual elevations may have taken place. Every one 

 who has given attention to what goes on at the bottom of 

 rivers, on the margins of lakes, in estuaries, and on the sea 

 coast, knows that loose matter may assume under water 

 various forms, often fantastic, according to the direction, 

 force, and interference of currents with each other. The ob- 

 servations made during a long series of years have not led 

 me to swerve from the conviction, that, after the land had 

 assumed its present aspect and position in relation to the 

 sea, or at the time when the land was broken up into its present 

 condition, a vast body of water has passed over it. It is little 

 short of half a century since Sir James Hall made me ac- 

 quainted with the facts which led him to the conclusions 

 wliich he published in the Edinburgh Transactions ; and no- 

 thing I have seen or been informed of since has contributed 

 to change my views in refei'cncc to his conclusions ; though 



