e-fields, and standing stones.
The loch itself, an expansive sheet of water fourteen miles in
circumference, I contemplated with much interest, and longed for an
opportunity of studying its natural history. Two promontories,--those
occupied by the Standing Stones, shoot out from the opposite sides, and
approach so near as to be connected by a rustic bridge. They divide the
loch into two nearly equal parts, the lower of which gives access to the
sea, and is salt in its nether reaches and brackish in its upper ones,
while the higher is merely brackish in its nether reaches, and fresh
enough in its upper ones to be potable. The shores of both were strewed,
at the time I passed, by a line of wrack, consisting, for the first few
miles, from where the lower loch opens to the sea, of only marine
plants, then of marine plants mixed with those of fresh-water growth,
and then, in the upper sheet of water, of lacustrine plants exclusively.
And the fauna of the loch, like its flora, is, I was led to understand,
of the same mixed character; the marine and fresh-water animals having
each their own reaches, with certain debatable tracts between, in which
each expatiates with more or less freedom, according to its nature and
constitution,--some of the sea-fishes advancing far on the fresh water,
and others, among the proper denizens of the lake, encroaching far on
the salt. The common fresh-water eel strikes out, I was told, farthest
into the sea-water; in which, indeed, reversing the habits of the
salmon, it is known in various places to deposit its spawn; it seeks,
too, impatient of a low temperature, to escape from the cold of winter,
by taking refuge in water brackish enough in a climate such as ours to
resist the influence of frost. Of the marine fishes; on the other hand,
I found that the flounder got greatly higher than any of the others,
inhabiting reaches of the lake almost entirely fresh. A memoir on the
Loch of Stennis and its productions, animal and vegetable, such as a
Gilbert White of Selborne could produce, would be at once a very
valuable and very curious document. By dividing it into reaches, in
which the average saltness of the water was carefully ascertained, and
its productions noted, with the various modifications which these
underwent as they receded upwards or downwards from their proper habitat
towards the line at which they could no longer exist, much information
might be acquired, of a kind important to the natu