MAPS AS GEOGRAPHICAL ILLUSTRATIONS 491 
THE SCOTCH HIGHLANDS AND THE GREAT GLEN, 
SileetsuS4, 5A, 02, Os Zon O2, OR. 
The Highlands of Scotland are described by Sir Archibald 
Geikie in his Scenery of Scotland (2d edition) as an ancient 
mountain region, reduced to a plain of moderate inequality by 
atmospheric and marine denudation, and then broadly elevated 
and dissected. Since the dissection, the region has been heavily 
glaciated and moderately depressed; thus the lochs and the 
fiords are explained; Professor James Geikie’s Great Ice Age 
(3d edition) being the best reference on this part of the subject. 
The group of sheet here selected includes the western part of 
the Grampian Hills (the Highlands next north of the Lowlands), 
as well as part of the more northern Highlands and of the Great 
glen by which the northern and southern Highlands are obliquely 
separated. The chief characteristic of this rugged region is the 
thorough, mature dissection of the ancient peneplain in which 
the glens are carved, and the absence of definite trends in the 
course of the smaller ridges and glens. It seems as if the struc- 
ture of the uplifted plain of denudation were so massive that the 
processes of dissection in the present cycle of erosion found few 
distinct guides to direct their course. The Great glen, which 
is said to follow an ancient structural line of deformation and 
weakness, is almost the only example of topographic form that 
persists in maintaining a definite course for a considerable dis- 
tance. 
Among the special features of this region may be mentioned : 
Ben Nevis, the highest of the Scotch summits, although only 
about four miles from the head of Loch Linnhe, a long arm of 
the sea that enters far into the trough of the Great glen; several 
straths, or broad valley floors, such as Straths Spey and Spean, 
the seat of the greater part of the scanty Highland population; 
the frequent low level and comparatively flat divides on glen or 
strath floors between opposing streams; several large lakes, such 
as Lochs Lochy and Ness in the axis of the Great glen, with 
Quoich and Arkaig on the northand Treig and Etive on the south 
in subordinate glens, all these and their fellows being ascribed to 
