s could scarce be produced, had contrast
for effect's sake been the object. On landing on the exposed shelf to
which we had fastened our halser, I found the origin of the sand
interestingly exhibited. The hollows of the rock, a rough trachyte, with
a surface like that of a steel rasp, were filled with handfuls of broken
shells thrown up by the surf from the sea-banks beyond: fragments of
echini, bits of the valves of razor-fish, the island cyprina, mactridae,
buccinidae, and fractured periwinkles, lay heaped together in vast
abundance. In hollow after hollow, as I passed shorewards, I found the
fragments more and more comminuted, just as, in passing along the
successive vats of a paper-mill, one finds the linen rags more and more
disintegrated by the cylinders; and immediately beyond the inner edge of
the shelf, which is of considerable extent, lies the flat bay, the
ultimate recipient of the whole, filled to the depth of several feet,
and to the extent of several hundred yards, with a pure shell-sand, the
greater part of which had been thus washed ashore in handfuls, and
ground down by the blended agency of the trachyte and the surf. Once
formed, however, in this way it began to receive accessions from the
exuviae of animals that love such localities,--the deep arenaceous bed
and soft sand-beach; and these now form no inconsiderable proportion of
the entire mass. I found the deposit thickly inhabited by spatangi,
razor-fish, gapers, and large, well-conditioned cockles, which seemed to
have no idea whatever that they were living amid the debris of a charnel
house. Such has been the origin here of a bed of shell-sand, consisting
of many thousand tons, and of which at least eighty per cent. was once
associated with animal life. And such, I doubt not, is the history of
many a calcareous rock in the later secondary formations. There are
strata, not a few, of the Cretaceous and Oolitic groups, that would be
found--could we but trace their beginnings with a certainty and
clearness equal to that with which we can unravel the story of this
deposit--to be, like it, elaborations from dead matter, made through the
agency of animal secretion.

We set out on our first exploratory ramble in Eigg an hour before noon.
The day was bracing and breezy, and a clear sun looked cheerily down on
island, and strait, and blue open sea. We rowed southwards in our
little boat, through the channel of Eilean Chaisteil, along the
trap-rocks of the i