e may be counterfeited or made by
art and design, as may also books, manuscripts, and inscriptions, as all
the learned are now sufficiently satisfied has often been actually
practised," &c.; "and though it must be granted that it is very
difficult to read them (the records of nature) and _to raise a
chronology out of them_, and to state the intervals of the time wherein
such or such catastrophes and mutations have happened, yet it is not
impossible."[58]

Respecting the extinction of species, Hooke was aware that the fossil
ammonites, nautili, and many other shells and fossil skeletons found in
England, were of different species from any then known; but he doubted
whether the species had become extinct, observing that the knowledge of
naturalists of all the marine species, especially those inhabiting the
deep sea, was very deficient. In some parts of his writings, however,
he leans to the opinion that species had been lost; and in speculating
on this subject, he even suggests that there might be some connection
between the disappearance of certain kinds of animals and plants, and
the changes wrought by earthquakes in former ages. Some species, he
observes, with great sagacity, are "_peculiar to certain places_, and
not to be found elsewhere. If, then, such a place had been swallowed up,
it is not improbable but that those animate beings may have been
destroyed with it; and this may be true both of aerial and aquatic
animals; for those animated bodies, whether vegetables or animals, which
were naturally nourished or refreshed by the air, would be destroyed by
the water," &c.[59] Turtles, he adds, and such large ammonites as are
found in Portland, seem to have been the productions of hotter
countries; and it is necessary to suppose that England once lay under
the sea within the torrid zone! To explain this and similar phenomena,
he indulges in a variety of speculations concerning changes in the
position of the axis of the earth's rotation, "a shifting of the earth's
centre of gravity, analogous to the revolutions of the magnetic pole,"
&c. None of these conjectures, however, are proposed dogmatically, but
rather in the hope of promoting fresh inquiries and experiments.

In opposition to the prejudices of his age, we find him arguing against
the idea that nature had formed fossil bodies "for no other end than to
play the mimic in the mineral kingdom;"--maintaining that figured stones
were "really the several bodies they r