within a few yards of the granitic block. And now, yielding to the
undermining influences, just as a blinding snow-shower is darkening the
heavens, it comes thundering down the steep into the sea, where it lies
immediately beneath the high-water line, surrounded by a wide float of
pulverized ice, broken by the waves. A keen frost sets in; the
half-fluid mass around is bound up for many acres into a solid raft,
that clasps fast in its rigid embrace the rocky fragment; a stream-tide,
heightened by a strong gale from the west, rises high on the beach; the
consolidated ice-field moves, floats, is detached from the shore, creeps
slowly outwards into the offing, bearing atop the boulder; and,
finally, caught by the easterly current, it drifts away into the open
ocean. And then, far from its original bed in the rock, amid the
jerkings of a cockling sea, the mass breaks through the supporting
float, and settles far beneath, amid the green and silent twilight of
the bottom, where its mosses and lichens yield their place to stony
encrustations of deep purple, and to miniature thickets of arboraceous
zoophites.

The many-colored Acalephae float by; the many-armed Sepiadae shoot over;
while shells that love the profounder depths,--the black Modiola and
delicate Anomia,--anchor along the sides of the mass; and where thickets
of the deep-sea tangle spread out their long, streamer-like fronds to
the tide, the strong Cyprina and many-ribbed Astarte shelter by scores
amid the reticulations of the short woody stems and thick-set roots. A
sudden darkness comes on, like that which fell upon Sinbad when the
gigantic roc descended upon him; the sea-surface is fully sixty fathoms
over head; but even at this great depth an enormous iceberg grates
heavily against the bottom, crushing into fragments in its course,
Cyprina, Modiola, Astarte, with many a hapless mollusc besides; and
furrows into deep grooves the very rocks on which they lie. It passes
away; and, after many an unsummed year has also passed, there comes
another change. The period of depression and of the boulder-clay is
over. The water has shallowed as the sea-line gradually sank, or the
land was propelled upwards by some elevatory process from below; and
each time the tide falls, the huge boulder now raises over the waters
its broad forehead, already hung round with flowing tresses of brown
sea-weed, and looks at the adjacent coast. The country has strangely
altered its features: