Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/344

 difficulties sufficiently perplexing in the latter case, were rendered impracticable in the former, while the nature of the past summer, 1816, and that of the preceding, 1815, not less unfavourable in the western highlands, have made it utterly impossible to renew the investigation, originally made in 1814.

From this cause I am unable to assert positively that there is an identity of level between the lines of Glen Roy and those which occur in Glen Gloy, although it will hereafter be seen that there is but little, if any, reason to doubt it. I shall describe the appearances as far as I was able to observe them; when the reasons for acquiescing in their common origin will appear.

On entering Glen Gloy from Lowbridge no trace of a libe can be perceived for about three miles. The marks of three are then to be seen on the salient angle of a green hill on the left bank of the stream. As far as the eye can judge of their relative distances (for I was unable to measure them) they appear to correspond to those of Glen Roy: but the upper and lower one soon terminate, while the middle one is continued for some little way up the valley. On the right side of the stream, opposite to them, a very strongly marked line of considerable breadth occurs, extending up the valley for a long space beyond the reach of the eye, accompanied by an inferior one far less persistent.

Being prevented from tracing this valley into Glen Roy, I attempted to examine it in the opposite direction by entering from Glen Turit. I have shewn that the lines of Glen Roy terminate at the head of Glen Turit, in consequence of its elevation by which their progress is at length naturally terminated. From this point which separates the head of this glen from that of Glen Gloy, since it is the common boundary of both, no line can be seen for a space of three or four miles; at which point one commences on the right