ON THE PARALLEL ROADS 



taining the horizontality of the lines. The weather was par- 

 ticularly favourable for our purpose, having been remarkably 

 calm and clear during the whole of our stay in Lochaber. We 

 had also the good fortune to be hospitably received, as the 

 guests of Mr Macdonell of Inch, whose residence, situated 

 near the junction of the rivers Roy and Spean, afforded us the 

 most centrical point, from whence we might make excursions 

 in every direction ; whilst extreme acuteness of observation in 

 our host, and the great interest he has taken for many years, in 

 the very investigation in which we were engaged, and the con- 

 stant opportunity he has had of making himself acquainted with 

 the various appearances, rendered him an intelligent, as well as 

 a willing guide. I am, therefore, now enabled to offer an ac- 

 count of these shelves, not only much more particular, but 

 embracing a much greater extent of country. And although 

 I am well aware of the numerous sources of error to which the 

 investigator of so many intricate mazes is exposed, yet I trust 

 I may venture to hope, that my inaccuracies are few in num- 

 ber, and, individually, unimportant. In this hope I am the more 

 confident, from having the highly valuable testimony of Mr 

 Macdonell of Inch to support me, from whose communica- 

 tions I have even described some particular spots, which I had 

 not an opportunity of visiting in person. Indeed I cannot suf- 

 ficiently express my sense of the obligations I owe to that gen- 

 tleman. 



In the first part of my essay, I propose to give a general 

 description of the form and appearance of the shelves. I shall 

 next suggest the theory, which may account for the formation 

 of such appearances in general. I shall then give a particular 

 account of the whole shelves of Lochaber, as connected with the 

 topography of the glens where they are found. And, lastly, I 

 shall conclude, by stating the theory, which appears to me most 



likely 



