with the dip. When taken out, they remind one of water-worn pebbles, or
rather boulders of a shore. A smart blow on the edge splits them along
on the major axis, and exposes the interesting inclosure. The practised
geologist knows well the thrilling interest attending the breaking up of
the nodule: the uninitiated cannot sympathize with it. There is no time
when a fossil looks so well as when first exposed. There is a clammy
moisture on the surface of the scales or plates, which brings out the
beautiful coloring, and adds brilliancy to the enamel. Exposure to the
weather soon dims the lustre; and even in a cabinet an old specimen is
easily known by its tarnished aspect."

I found at Clune no ichthyolite to which the geologists have not been
already introduced, or with which I had not been acquainted previously
in the Cromarty beds. The Lower Old Red of Morayshire furnishes,
however, at least one genus not yet figured nor described, and of which,
so far as I am aware, only a single specimen has yet been found. It
seems to have been a small delicately-formed fish; its head covered with
plates; its body with round scales of a size intermediate between those
of the Osteolepis and Cheiracanthus; its anterior dorsal fin placed, as
in the Dipterus, Diplopterus, and Glyptolepis, directly opposite to its
ventral fins; the enamelled surfaces of the minute scales were fretted
with microscopic undulating ridges, that radiated from the centre to the
circumference; similar furrows traversed the occipital plates; and the
fins, unfurnished with spines, were formed, as in the Dipterus and
Diplopterus, of thick-set, enamelled rays. The posterior fins and tail
of the creature were not preserved. I may mention, for the satisfaction
of the geologist, that I saw this unique fossil in the possession of the
late Lady Cumming of Altyre, a few weeks previous to the lamented death
of her ladyship; and that, on assuring her it was as new in relation to
the Cromarty and Caithness fish-beds as to those of Moray, she intimated
an intention of forthwith sending a drawing of it to Agassiz; but her
untimely decease in all probability interfered with the design, and I
have not since heard of this new genus of ichthyolite, or of her
ladyship's interesting specimen, hitherto apparently its only
representative and memorial. In the Morayshire, as in the Cromarty beds,
the limestone nodules take very generally the form of the fish which
they inclose: they ar