feet, its upper peaks and
ridges must overlie the bones, making allowance for the dip, to the
depth of at least sixteen hundred. Even at the close of the Oolitic
period this sepulchral stratum must have been a profoundly ancient one.
In working it out, I found two fine specimens of fish jaws, still
retaining their ranges of teeth;--ichthyodorulites,--occipital plates of
various forms, either reptile or ichthyic,--Ganoid scales, of nearly the
same varieties of pattern as those in the Weald of Morayshire,--and the
vertebrae and ribs, with the digital, pelvic, and limb-bones, of
saurians. It is not unworthy of remark, that in none of the beds of this
deposit did I find any of the more characteristic shells of the
system,--Ammonites, Belemnites, Gryphites, or Nautili.

I explored the shores of the island on to the _Ru Stoir_, and thence to
the Bay of Laig; but though I found detached masses of the reptile bed
occurring in abundance, indicating that its place lay not far beyond the
fall of ebb, in no other locality save the one described did I find it
laid bare. I spent some time beside the Bay of Laig in reexamining the
musical sand, in the hope of determining the peculiarities on which its
sonorous qualities depended. But I examined, and cross-examined it in
vain. I merely succeeded in ascertaining, in addition to my previous
observations, that the loudest sounds are elicited by drawing the hand
slowly through the incoherent mass, in a segment of a circle, at the
full stretch of the arm, and that the vibrations which produce them
communicate a peculiar titillating sensation to the hand or foot by
which they are elicited, extending in the foot to the knee, and in the
hand to the elbow. When we pass the wet finger along the edge of an
ale-glass partially filled with water, we see the vibrations thickly
wrinkling the surface: the undulations which, communicated to the air,
produce sound, render themselves, when communicated to the water,
visible to the eye; and the titillating feeling seems but a modification
of the same phenomenon acting on the nerves and fluids of the leg or
arm. It appears to be produced by the wrinklings of the vibrations, if I
may so speak, passing along sentient channels. The sounds will
ultimately be found dependent, I am of opinion, though I cannot yet
explain the principle, on the purely quartzose character of the sand,
and the friction of the incoherent upper strata against under strata
coherent an