I will now give a few examples to illustrate these remarks; and to show
how liable we are to error in supposing that whole groups of species
have suddenly been produced. I may recall the well-known fact that in
geological treatises, published not many years ago, the great class of
mammals was always spoken of as having abruptly come in at the
commencement of the tertiary series. And now one of the richest known
accumulations of fossil mammals belongs to the middle of the secondary
series; and one true mammal has been discovered in the new red
sandstone at nearly the commencement of this great series. Cuvier used
to urge that no monkey occurred in any tertiary stratum; but now
extinct species have been discovered in India, South America, and in
Europe even as far back as the eocene stage. The most striking case,
however, is that of the Whale family; as these animals have huge bones,
are marine, and range over the world, the fact of not a single bone of
a whale having been discovered in
any secondary formation, seemed fully to justify the belief that this
great and distinct order had been suddenly produced in the interval
between the latest secondary and earliest tertiary formation. But now
we may read in the Supplement to Lyell s Manual, published in 1858,
clear evidence of the existence of whales in the upper greensand, some
time before the close of the secondary period.
I may give another instance, which from having passed under my own eyes
has much struck me. In a memoir on Fossil Sessile Cirripedes, I have
stated that, from the number of existing and extinct tertiary species;
from the extraordinary abundance of the individuals of many species all
over the world, from the Arctic regions to the equator, inhabiting
various zones of depths from the upper tidal limits to 50 fathoms; from
the perfect manner in which specimens are preserved in the oldest
tertiary beds; from the ease with which even a fragment of a valve can
be recognised; from all these circumstances, I inferred that had
sessile cirripedes existed during the secondary periods, they would
certainly have been preserved and discovered; and as not one species
had been discovered in beds of this age, I concluded that this great
group had been suddenly developed at the commencement of the tertiary
series. This was a sore trouble to me, adding as I thought one more
instance of the abrupt appearance of a great group of species. But my
work had hardly been published, when a skilful pal ontologist, M.
Bosquet, sent me a drawing of a perfect specimen of an unmistakeable
230