The loch of Dowalton was of an irregular form, about 1½ mile long,
and about three-quarters of a mile in greatest breadth, and without
any marked outfall for drainage. Sir William Maxwell effected this
by making a cut, 25 feet deep, through the wall of whinstone and
slate which closed it in at its south-eastern boundary. When the
waters were allowed to run off in the summer of 1863 no less than
five artificially constructed islands became visible. One of these
had a cairn of stones on it which always remained above water, and
was known as the "Miller's Cairn," from the fact of its having been
used, like the Nilometer, to measure the quantity of water in the
lake, and thereby to regulate its supply to neighbouring mills. "On
approaching the cairn," says Dr. Stuart, "the numerous rows of piles
which surrounded it first attracted notice. These piles were formed of
young oak-trees. Lying on the north-east were mortised frames of beams
of oak, like hurdles, and, below these, round trees laid horizontally.
In some cases the vertical piles were mortised into horizontal bars.
Below them were layers of hazel and birch branches, and under these
were masses of ferns, the whole mixed with large boulders, and
penetrated by piles. Above all was a surface of stone and soil, which
was several feet under water till the recent drainage took place. The
hurdle frames were neatly mortised together, and were secured by pegs
in the mortise holes. On one side of the island a round space of a few
feet in size appeared, on which was a layer of white clay, browned
and calcined as from the action of fire, and around it were bones of
animals and ashes of wood.... Lines of piles, apparently to support a
causeway, led from it to the shore." (B. 94.)
The other islands were constructed in a similar manner, and of
like materials. The largest and farthest from the shore measured
twenty-three yards in diameter, and its surface was three feet lower
than that of the others. Several canoes and bronze dishes were found
in the mud in the vicinity of these islands, and in making excavations
on them many relics and broken bones were collected, of which the
following is a list as far as known up to the present time:--