effects apparently of eddy winds whirling round,
as on a pivot, the decayed plants; and yet further, that footprints,
especially those of rabbits and birds, were not unfrequent in the waste.
And as lines of stratification were, I found, distinctly preserved in
the formation, I deemed it not improbable that, in cases in which high
winds had arisen immediately after tracts of wet weather, and covered
with sand, rapidly dried on the heights, the damp beds in the hollows,
both the circular markings and the footprints might remain fixed in the
strata, to tell of their origin. I found in several places, in chasms
scooped out by a recent gale, pieces of the ancient soil laid bare,
which had been covered up by the sand-flood nearly two centuries before.
In one of the openings the marks of the ancient furrows were still
discernible; in another, the thin stratum of ferruginous soil had
apparently never been brought under the plough; and I found it charged
with roots of the common brake (_Pteris aquilina_), in a perfect state
of keeping, but black and brittle as coal. Beneath this layer of soil
lay a thin deposit of the stratified gravel of what is now known as the
later glacial period--the age of _osars_ and moraines; and beneath
all--for the underlying Old Red Sandstone of the district is not exposed
amid the level wastes of Culbin--rested the boulder clay, the memorial
of a time of submergence, when Scotland sat low in the sea as a wintry
archipelago of islands, brushed by frequent icebergs, and when
sub-arctic molluscs lived in her sounds and bays. A section of a few
feet in vertical extent presented me with four distinct periods. There
was, first, the period of the sand-flood, represented by the bar of
pale-sand; then, secondly, the period of cultivation and human
occupancy, represented by the dark plough-furrowed belt of hardened
soil; thirdly, there was the gravel; and, fourthly, the clay. And that
shallow section exhausted the historic ages, and more; for the double
band of gravel and clay belonged palpably to the geologic ages, ere man
had appeared on our planet. There had been found in the locality, only a
few years previous to this time, a considerable number of stone
arrow-heads--some of them only partially finished, and some of them
marred in the making, as if some fletcher of the stone age had carried
on his work on the spot; and all these memorials of a time long anterior
to the first beginnings of history in the isla