THE 



EDINBURGH NEW 



PHILOSOPHICAL JOUENAL. 



An Attempt to classify the Phenomena in the Glens of Lochaher 

 with those of the Diluvium, or Drift, which covers the face of 

 the Country. By Sir G. S. MACKENZIE, Bart., F.B.S., 

 V.P.R.S.E., &c. With a Map. Communicated by the 

 Author. 



TuE notion respecting the origin of the terraces or shelves 

 in tlie Glens of Lochaber, which was entertained on their 

 being first discovered, viz : — that they were productions of 

 art, is scarcely worthy of being mentioned, except for the 

 purpose of remarking as singular, that they still retain the 

 name of " the Parallel Roads," indicating that the impression 

 of their being artificial had been exceedingly strong. When 

 it came to be universally admitted that the formation of the 

 shelves was natural, and that the operating power had been 

 water, difficulties presented themselves in every inquii'y into 

 the mode in which the water had been brought to act, and 

 into that by which it had been removed. Geologists are as 

 far from coming to an agreement as ever ; and the interest 

 in the phenomena is reviving. 



It is now more than twelve years since I briefly announced 

 in Sir David Brewster's Philosophical Journal, a new expla- 

 nation of the origin of these terraces, which occurred to me 

 during a conversation with him, when he resided on the banks 

 of the Spey. In January, 1842, I read a more extended ac- 

 count of my views before the Royal Society of Edinburgh, 

 in which I noticed Mr Darwin's theory ; but I delayed to 

 publish my observations, in tlie expectation of being able to 



VOL. XLIV. NO. LXNXVII. — JAN. 1848. A 



