14 ON THE PARALLEL ROADS 



That theory seems to me infinitely the most probable, which 

 attributes the formation of the shelves to the action of the wa- 

 ters of a lake. The perfect horizontality of the lines, and their 

 exact agreement in height on the opposite mountains, added 

 to the fact of their running up the smaller tributary glens, and 

 following the retiring, as well as the projecting parts of the fl- 

 ees of the mountains, with so much regularity and precision, 

 — the circumstance of their encircling isolated hills with a per- 

 fect ring, totally unconnected with any other part of the 

 shelves, — the rounded edges of the rocks, and fragments on 

 their lines, — the change which takes place in the soil above 

 and below the shelves, — their expansion into mossy flats or in- 

 clined planes, whenever the level forces them to do so, — all 

 combine to show, that nothing but the surface of water could 

 have caused them. That alpine lakes, filling deep hollows 

 amidst mountains, rising from their bottoms with steep and al- 

 most precipitous acclivities, do generally form similar shelves 

 around their margins, must be sufficiently well known to eve- 

 ry one who has had an opportunity of visiting such scenes. 

 Indeed a little reflection will show, that this must necessarily 

 happen. For if we suppose the almost perpendicular sides of 

 such a hollow to be filled, to a considerable height, with a lake 

 of this character, as exemplified in the diagram, (Plate VII. 

 fig. 5.), in which the dotted line A represents its level, then 



the 



" and, indeed, till within this century, the valley was covered with wood, which 

 "" made it very difficult to pursue the deer, &c. and rendered certain avenues ne- 

 " cessary for effecting this purpose ; in corroboration of which opinion, it may be 

 " observed, that upon the sides of the roads, there have been found some stakes 

 " fixed in the ground, probably the remains of some of the paling or fences, which 

 " in those days were made use of to confine the game, till they were driven in 

 " upon a field, called DaLna-sealg, or Hunting Dale, where the presumption is 

 " they were killed." 



