the places of
the spiky points on the hybodent teeth. I have got three of each kind
slit up by Mr. George Sanderson, and the internal structure appears to
be the same. A dense body of bone is traversed by what seem innumerable
roots, resembling those of woody shrubs laid bare along the sides of
some forest stream. Each internal opening sends off on every side its
myriads of close-laid filaments; and nowhere do they lie so thickly as
in the line of the enamel, forming, from the regularity with which they
are arranged, a sort of framing to the whole section. It is probable
that the Hybodus,--a genus of shark which became extinct some time about
the beginning of the chalk,--united, like the shark of Port Jackson, a
crushing apparatus of palatal teeth to its lines of cutting ones. Among
the other remains of these beds I found a dense fragment of bone,
apparently reptilian, and a curious dermal plate punctulated with
thick-set depressions, bounded on one side by a smooth band, and
altogether closely resembling some saddler's thimble that had been cut
open and straightened.

Following the beds downwards along the beach, I found that one of the
lowest which the tide permitted me to examine,--a bed colored with a
tinge of red,--was formed of a denser limestone than any of the others,
and composed chiefly of vast numbers of small univalves resembling
Neritae. It was in exactly such a rock I had found, in the previous year,
the reptile remains; and I now set myself, with no little eagerness, to
examine it. One of the first pieces I tore up contained a well-preserved
Plesiosaurian vertebra; a second contained a vertebra and a rib; and,
shortly after, I disinterred a large portion of a pelvis. I had at
length found, beyond doubt, the reptile remains _in situ_. The bed in
which they occur is laid bare here for several hundred feet along the
beach, jutting out at a low angle among boulders and gravel, and the
reptile remains we find embedded chiefly in its under side. It lies low
in the Oolite. All the stratified rocks of the island, with the
exception of a small Liasic patch, belong to the Lower Oolite, and the
reptile-bed occurs deep in the base of the system,--low in its relation
to the nether division, in which it is included. I found it nowhere
rising to the level of high-water mark. It forms one of the foundation
tiers of the island, which, as the latter rises over the sea in some
places to the height of about fourteen hundred