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of Edinburgh, Session 1871 - 72 . 
the Lowes at its upper end. These streams, though short, are 
voluminous, because constantly supplied by numberless hill tribu¬ 
taries. 
A traveller on the loch-side sees no peat anywhere. The dis¬ 
trict was therefore pronounced by recent one-eyed visitors to be 
free from peat. An inquisitive observer might have suspected the 
reverse from one of the highest surrounding hills being called 
Peat-Law ; and on the high sky-line of another, a telescope would 
have betrayed to him a very suspicious circumstance in a crowd of 
little peat-stacks. Any one, not content with creeping along the 
bottom of valleys, but familiar with the summits of the mountains 
of the Scottish Lowlands, would then have known that the sky¬ 
line seen from the loch-side is not,—as it very often is in the 
primitive mountains of the Highlands,—a mere ridge, but forms 
the edge of a great table-top, which, in most cases, is chiefly com¬ 
posed of peat. In point of fact Professor G-eikie has shown last 
summer, from the (Government (Geological Survey, that a vast pro¬ 
portion of the hill-tops in the St Mary’s district consists of peat 
table-lands. 
The consequences 'which flow from this structure of the country 
are peculiar. In dry weather the high peaty summits of the hills 
will cease to supply moisture enough to drain into the streamlets 
which score their sides. These will then convey to the lake chiefly 
the drainage of the grassy slopes, and the produce of the scanty 
springs in the lower regions. But wLen a rain-flood sets in, the 
peat, whether previously dry or moist, will send down a profusion 
of peaty water. Had the Yarrow flow r ed as a river through the 
vale at St Mary’s, the peaty flood would have been swept quickly 
down towards the sea; and in two or three days the waters would 
have recovered from their peaty impregnation. But the two lochs, 
with a superficial area of two square miles, store up the peaty 
water, and dole it out, like a compensation pond, for many days, 
until the arrival of a fresh flood to renew it. An embankment at 
the outlet, to increase the storage, would protract the outflow, 
and postpone still further the recovery of the water from impurity. 
These facts and views could only occur to one familiar with the 
district, or going thither to study it for a practical object. When 
I first went to St Mary’s Loch on the 12th and 13th June last, I 
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VOL. VII. 
