than a
century ago, to weigh up the Florida, which ended in the weighing up of
merely a few of her guns, some of them of iron greatly corroded; and
that, on scraping them, they became so hot under the hand that they
could not be touched, but that they lost this curious property after a
few hours' exposure to the air. There have since been repeated instances
elsewhere, he adds, of the same phenomenon, and chemistry has lent its
solution of the principles on which it occurs; but, in the year 1740,
ere the riddle was read, it must have been deemed a thoroughly magical
one by the simple islanders of Mull. It would seem as if the guns,
heated in the contest with Drake, Hawkins, and Frobisher, had again
kindled, under some supernatural influence, with the intense glow of the
lost battle.

The morning was showery; but it cleared up a little after ten, and we
landed to explore. We found the mill a little to the south of the
village, where a small stream descends, all foam and uproar, from the
higher grounds along a rocky channel half-hidden by brushwood; and the
Liasic bed occurs in an exposed front directly over it, coped by a thick
bed of amygdaloidal trap. The organisms are numerous; and, when we dig
into the bank beyond the reach of the weathering influences, we find
them delicately preserved, though after a fashion that renders difficult
their safe removal. Originally the bed must have existed as a brown
argillaceous mud, somewhat resembling that which forms in the course of
years, under a scalp of muscles; and it has hardened into a more
silt-like clay, in which the fossils occur, not as petrifactions, but
as shells in a state of decay, except in some rare cases, in which a
calcareous nodule has formed within or around them. Viewed in the group,
they seem of an intermediate character, between the shells of the Lias
and the Oolite. One of the first fossils I disinterred was the Gryphaea
obliquata,--a shell characteristic of the Liasic formation; and the
fossil immediately after, the Pholadomy aequalis, a shell of the Oolitic
one. There occurs in great numbers a species of small Pecten,--some of
the specimens scarce larger than a herring scale; a minute Ostrea, a
sulcated Terebratula, an Isocardia, a Pullastra, and groups of broken
serpulae in vast abundance. The deposit has also its three species of
Ammonite, existing as mere impressions in the clay; and at least two
species of Belemnite,--one of the two somewhat resembli