ct species; and the
nicely-marked impression of part of a Cidaris, with the balls on which
the sockets of the club-like spines had been fitted existing in the
print as spherical moulds, in which shot might be cast, and with the
central ligamentary depression, which in the actual fossil exists but as
a minute cavity, projecting into the centre of each hollow sphere, like
the wooden fusee into the centre of a bomb-shell. This latter cast, fine
and sharp as that of a medal taken in sulphur, seems sufficient of
itself to establish two distinct points: in the first place, that the
siliceous matter of which the flint is composed, though now so hard and
rigid, must, in its original condition, have been as impressible as wax
softened to receive the stamp of the seal; and, in the next, that though
it was thus yielding in its character, it could not have greatly shrunk
in the process of hardening. I looked with no little interest on these
remains of a Scotch formation now so entirely broken up, that, like
those ruined cities of the East which exist but as mere lines of
wrought material barring the face of the desert, there has not "been
left one stone of it upon another," but of which the fragments, though
widely scattered, bear imprinted upon them, like the stamped bricks of
Babylon, the story of its original condition, and a record of its
_founders_. All Mr. Longmuir's Cretaceous fossils from the hill of
Dudwick are of flint,--a substance not easily ground down by the
denuding agencies.

I found several other curious fossils in Mr. Longmuir's collection.
Greatly more interesting, however, than any of the specimens which it
contains, is the general fact, that it should be the collection of a
Free Church minister, sedulously attentive to the proper duties of his
office, but who has yet found time enough to render himself an
accomplished geologist; and whose week-day lectures on the science
attract crowds, who receive from them, in many instances, their first
knowledge of the strange revolutions of which our globe has been the
subject, blent with the teachings of a wholesome theology. The present
age, above all that has gone before, is peculiarly the age of physical
science; and of all the physical sciences, not excepting astronomy
itself, geology, though it be a fact worthy of notice, that not one of
our truly accomplished geologists is an infidel, is the science of which
infidelity has most largely availed itself. And as the the