hy of notice in the stone of
which the two boulders of the Dog-stack are composed. No species of rock
occurs more abundantly in the embedded pebbles of this ancient
conglomerate than rocks of the trap family. We find in it
trap-porphyries, greenstones, clinkstones, basalts, and amygdalolds,
largely mingled with fragments of the granitic, clay-slate, and quartz
rocks. The Plutonic agencies must have been active in the locality for
periods amazingly protracted; and many of the masses protruded at a very
early time seem identical in their composition with rocks of the trap
family, which in other parts of the country we find referred to much
later eras. There occur in this deposit rolled pebbles of a basalt,
which in the neighborhood of Edinburgh would be deemed considerably more
modern than the times of the Mountain Limestone, and in the Isle of
Skye, considerably more modern than the times of the Oolite.

The sunlight was showering its last slant rays on island and loch, and
then retreating upwards along the higher hills, chased by the shadows,
as our boat quitted the bay of Oban, and stretched northwards, along the
end of green Lismore, for the Sound of Mull. We had just enough of day
left, as we reached mid sea, to show us the gray fronts of the three
ancient castles,--- which at this point may be at once seen from the
deck,--Dunolly, Duart, and Dunstaffnage; and enough left us as we
entered the Sound, to show, and barely show, the Lady Rock, famous in
tradition, and made classic by the pen of Campbell, raising its black
back amid the tides, like a belated porpoise. And then twilight
deepened into night, and we went snorting through the Strait with a
stream of green light curling off from either bow in the calm, towards
the high dim land, that seemed standing up on both sides like tall
hedges over a green lane. We entered the Bay of Tobermory about
midnight, and cast anchor amid a group of little vessels. An exceedingly
small boat shot out from the side of a yacht of rather diminutive
proportions, but tautly rigged for her size, and bearing an outrigger
astern. The water this evening was full of phosphoric matter, and it
gleamed and sparkled around the little boat like a northern aurora
around a dark cloudlet. There was just light enough to show that the
oars were plied by a sailor-like man in a Guernsey frock, and that
another sailor-like man,--the skipper, mayhap,--attired in a cap and
pea-jacket, stood in the stern.