we afterwards find reptiles, but those which first appear belong to the
highest order of the class, and show no links of an insensible gradation
into fishes. In the tertiary deposit of the London clay the evidence of
concatenation entirely fails. Among the millions of organic forms, from
corals up to mammalia of the London and Paris basins, hardly a single
secondary species is found. In the south of France it is said that two
or three secondary species struggle into the tertiary strata; but they
form a rare and evanescent exception to the general rule. Organic nature
at this stage seems formed on a new pattern--plants as well as animals
are changed. It might seem as if we had been transported to a new
planet; for neither in the arrangement of the genera and the species,
nor in their affinities with the types of a pre-existing world, is there
any approach to a connected chain of organic development.

For some discrepancies the author endeavours to account, and it is fair
to give his explanation:--

"Fossil history has no doubt still some obscure passages; and these
have been partially adverted to. Fuci, the earliest vegetable
fossils as yet detected, are not, it has been remarked, the lowest
forms of aquatic vegetation; neither are the plants of the
coal-measures the very lowest, though they are a low form, of land
vegetation. There is here in reality no difficulty of the least
importance. The humblest forms of marine and land vegetation are of
a consistence to forbid all expectation of their being preserved in
rocks. Had we possessed, contemporaneously with the fuci of the
Silurians, or the ferns of the carboniferous formation, fossils of
higher forms respectively, _equally unsubstantial_, but which had
survived all contingencies, then the absence of mean forms of
similar consistency might have been a stumbling-block in our