Dr. Mac Culloch on the Parallel Roads of Glen Roy. 353 



on which this explanation proceeds, as it would lead into discussions 

 foreign to the views of this paper, and as it is undoubtedly sup- 

 ported by a sufficient mass of evidence. 



It is proper however before entering on this examination to recal 

 to the reader the general disposition of the lines, and that of the 

 vallies which they occupy. They are found commencing within a 

 very short distance of that summit which is the common origin of 

 the waters of the Spey and Roy, the one running to the east, the 

 other to the west. In their progress westward they increase in 

 number and in the perfection of their forms and markings, main- 

 taining the same level throughout : while the bottom of the valley, 

 now the course of the Roy, descends with a rapid declivity towards 

 its junction with the Spean. One of these lines is found ascending 

 the valley of the Spean for a few miles, and terminating in the great 

 common valley of the Spean and Roy, at a point agreeing with 

 that of its corresponding line which descends from the valley of the 

 Roy. From Glen Roy the same lines are continued into Glen 

 Turit, a valley opening into that of the Roy. Here they meet with 

 its bottom as it rises during their level progress, but they are re- 

 newed in Glen Gloy, a valley placed in a reverse direction to Glen 

 Turit, continuing throughout its descent in a course similar to 

 that which they held in Glen Roy, until they disappear near its 

 lower extremity and before its junction with the vale of the Lochy, 

 the common exit of Glen Gloy and the conjoined vallies of the 

 Roy and Spean. 



We are now to examine the probable course of the torrent or 

 deluge assumed to be the cause of these lines. It is most con- 

 sonant to the present state of things to imagine that it flowed from 

 east to west or from the source of the Roy towards its termination. 

 If it be conceived to have flowed in the reverse direction from the 



