Dr. Mac Culloch on the Parallel Roads of Glen Roy. 317 



Before examining any of the theories which have been proposed 

 to explain the singular appearance which this glen exhibits, I have 

 judged it expedient to describe with as much accuracy as possible 

 the appearances themselves, without entering on the question of 

 causes, or prejudging in any degree the case. In thus describing 

 it, I have preferred beginning at the source of the river, or rather 

 at the commencement of the valley, since the rivers which form 

 the Roy arise as mountain torrents, forming a junction in the middle 

 of a valley of considerable magnitude. 



A low hill of granite skirts the boundary between the source of 

 the Spey and the valley of the Roy. At the foot of this hill, in a 

 slightly elevated boggy plain, is found Loch Spey, which by a 

 declivity for some time scarcely perceptible runs eastward through 

 Badenoch to fall into the Moray firth. The western end of the 

 boggy plain just mentioned stretches for a few hundred yards 

 beyond the head of Loch Spey, and then descends by a sudden step 

 into the upper valley of Glen Roy. This valley is of an oval form, 



The principal map does not pretend to be an accurate survey. The defective nature 

 of all the maps of Scotland hitherto constructed, as well as the smallness of their scales, 

 prevented me from making any use of them for this purpose; but as the description 

 would have been unintelligible without some sketch of the ground, I have given one 

 which must however be considered merely in the light of a military reconuoissance. 

 The sections do not pretend to be real. The transverse ones are, like the map, delineated 

 without attention to their true proportions, and are merely intended to mark the impor. 

 tant variations ef the form of the bottom of the valley, and more particularly the points 

 in which the lines and the terraces coincide. The curved longitudinal sections are equally 

 artificial, but they assist the imagination in pursuing the wide connections of Glen Roy 

 with the sea. The profiles of the lines are deduced from actual measurement by the 

 spirit level. 



Of the accompanying views I need only say that they arc intended to elucidate several 

 parts of the description, and to convey a slight notion of the nature of the appearances 

 in question. The purposes of the two other maps in shewing the connections of Glen 

 Roy with the neighbouring and with the more distant country will be obvious. 



Vol. iv. 2 s 



