234 ON THK NATURAL HISTORY OF THE SOUTH OF SCOTLAND. 
The low round hills which bound the valley, present the same characters as 
those described in the course of the Tweed, but are covered with a finer vegeta¬ 
tion, the gi’eater part being green, even to the summit. The soil is a mixture 
of clay and sand, with pebbles of grey-wacke, and the diluvial subsoil is of the 
same nature. 
As this district is celebrated for its pastures, one would naturally expect to 
find them of the finest quality ; but, in fact, they present nothing remarkable in 
their appearance. On the high grounds Calluna vulgaris is the predominant 
species, which, when allowed to grow, choaks up most of the other plants, al¬ 
though it does not attain a great height, and is not nearly so strong as in the 
West and North Highlands. When it has been burnt, several grasses, such as 
Nardus stricta, Aira Jlexuosa, Anthoxanthum odoratum^ and Agrostis vulgaris^ 
spring up or are developed, together with Juncus squarrosus^ J. acutiflorus^ a 
few Carices^ Eriophorum angustifoAum^ and the more ordinary heath plants, as 
Tormentilla officinalis^ Eolygala vulgaris^ Pedicularis sylvatica^ P. palustris and 
Bartsia odontites. A thick sward of young Heath, however, springs up, and 
the burning is renewed at intervals of a few years. In many places there is a 
profusion of Pteris aquilma and a few other Ferns, as Blechnum horeale, Aspi- 
dium jfilix-mas, and Polypodium vulgare^ make their appearance. In the 
marshy places the vegetation is similar to that of such grounds in other hilly 
districts. On the whole, the vegetation of the higher parts is not luxuriant, but 
it seems in general well adapted for cattle. That of the slopes and lower grounds 
differs in no respect, as to the species composing it, from the pasturage of the 
Pentland and Ochill Hills; but owing to the great proportion of Junci, Melica 
cmrulea^ Nardus stricta^ Scirpus ccespitosus^ and other Cyperacece^ is more 
verdant, and often produces dense crops, which might be cut with the scythe to 
a great extent. 
St. Mary’s Loch has been lauded beyond its deserts. Were it placed among 
the Grampians, it would attract little notice; but here, where one may wander 
whole days among uniform, smooth, grassy hills, without meeting with so much 
as a good peat bog, it does afford no ordinary degree of pleasure to the naturalist 
who for the first time views its smooth expanse embosomed among the pastoral 
mountains, the bright tints of which are reflected from its glassy surface. 
Perhaps a sheet of water is beautiful under any circumstances, unless indeed it 
be composed of an infusion of peat surrounded by bogs, like the lakes of Lewis 
and North Uist; but the beauty of a lake principally depends upon the character 
of the surrounding scenery. That of St. Mary’s Loch is of the most simple 
character, consisting entirely of rounded, uniform, mostly verdant hills, with steep 
slopes, covered with a coarse grassy vegetation, and occasionally some Fern. A 
few bushes and decayed trees add in a manner to the general nakedness, and 
