32 DESCRIPTION OF THE PHYSICAL FEATURES 
gusli out of the Assynt limestone cliffs, the transluceut, ultra- 
marine blue of the lakes near Durness, as well as the thick coating 
of lime incrusted upon the iron kettles and domestic pots and 
pans, not to speak of the delicious white-fleshed, crustacea-fed 
trout of the burns, all speak to the great beds of calcareous for- 
mation which underlie the gneiss, and crop out at various points 
in the west and north, and which, near the farm and shooting-box 
of Ledbeg, and again near Loch Alsh, harden and whiten into a 
very pure and white marble, long known and worked as Assynt 
marble. 
This limestone is a very marked feature in the landscape, and 
a not unimportant factor in the zoological conditions. Amongst 
these clear streams there is a rich crustacean fauna and other 
lower forms of animal life. We consider that the limestone of 
Durness has even left its impress upon the Salmonidae of its 
streams and lakes. 
The wild and rugged scenery of the west of Sutherland is not how- 
ever due entirely to the vast masses of mountain, nor even to their 
peculiar shapes and isolated positions, though undoubtedly these are 
very important factors. Besides the greater majesty of the hills, 
there are many wild and sinuous valleys and picturesquely-grouped 
combinations of lesser elevations, which introduce a charm which 
one might look for in vain if the hills stood alone in all their naked- 
ness. There are wooded lakes and birch-clad hollows, heathery 
knolls and grey lichen-covered boulders, sparkling rivers and 
cascades ; and there are the quaint, and quiet, and " bonny " peat- 
reek shealings, and closely-nestling crofts a,nd cabins — abundant 
scope for the artist, who complains of the vastness of the subjects 
presented by the higher mountains and wider valleys. 
Yet, again, we find bleak, water-sodden moors, with sedgy- 
margined lakes — the home of the dunlin and the golden plover, 
and haunted by the weird shriek of the rain-bird or red-throated 
diver {Golymhiis septentrionalis), — but these are mostly confined to 
the south-west of our western district, and to the bleak upland 
moors of Durness and Cape Wrath, in which latter district 
they roll along with vast wavy undulations, like a heather-clad 
