that occur in a single system. We reach the long flat bay of Dunnet, and
cross its waste of sands. The incoherent coils of the sand-worm lie
thick on the surface; and here a swarm of buzzing flies, disturbed by
the foot, rises in a cloud from some tuft of tangled sea-weed; and here
myriads of gray crustaceous sand-hoppers dart sidelong in the little
pools, or vault from the drier ridges a few inches into the air. Were
the trilobites of the Silurian system,--at one period, as their remains
testify, more than equally abundant,--creatures of similar habits? We
have at length arrived at the tall sandstone precipices of Dunnet, with
their broad decaying fronts of red and yellow; but in vain may we ply
hammer and chisel among them: not a scale, not a plate, not even the
stain of an imperfect fucoid appears. We have reached the upper boundary
of the Lower Old Red formation, and find it bordered by a desert devoid
of all trace of life. Some of the characteristic types of the formation
re-appear in the upper deposits; but though there is a reproduction of
the original works in their more characteristic passages, if I may so
speak, many of the readings are diverse, and the editions are all new.

It is one of the circumstances of peculiar interest with which Geology
at its present stage is invested, that there is no man of energy and
observation who may not rationally indulge in the hope of extending its
limits by adding to its facts. Mr. Dick, an intelligent tradesman of
Thurso, agreeably occupies his hours of leisure, for a few months, in
detaching from the rocks in his neighborhood their organic remains; and
thus succeeds in adding to the existing knowledge of palaeozoic life, by
disinterring ichthyolites which even Agassiz himself would delight to
figure and describe. Several of the specimens in my possession, which I
owe to the kindness of Mr. Dick, are so decidedly unique, that they
would be regarded as strangers in the completest geological museums
extant. It is a not uncurious fact, that when the Thurso tradesman was
pursuing his labors of exploration among rocks beside the Pentland
Frith, a man of similar character was pursuing exactly similar labors,
with nearly similar results, among rocks of nearly the same era, that
bound, on the coast of Cornwall, the British Channel. When the one was
hammering in "Ready-money Cove," the other, at the opposite end of the
island, was disturbing the echoes of "Pudding-Gno;" and scales, p