CR ON Be 
and Number of Animals in Geological Times. 283 
been gathered around the coast of any of the islands of the 
Pacific Ocean, as far as we know the local Ichthyological faune 
of those regions ; it is as great nearly as the whole number 
of fishes known from the shores of Great Britain. The same 
may be said of the fishes of Monte Bolca, or of Mount Lebanon, 
or of those of the white chalk of England, or of those of Solen- 
hofen, or of those of the lias of Lyme Regis; and if we pass 
to older deposits, to the old red sandstone even—thanks to 
Mr Miller, and to the investigations of other British and 
Russian geologists—do we not know from that old forma- 
tion as many fishes as from any of the more recent ones, or 
from any circumscribed marine basin ? and is not the variety 
which occurs among them at each period as great, though of 
of a different character in each, as the variety which occurs 
at the present day? So that it can be fairly said, that at all 
periods, fishes have presented as great a variety of forms, 
and as numerous species, as under corresponding circum- 
stances at the present day. 
_ The class of Reptiles will allow similar conclusions ; for 
though the giants of the class have chiefly been studied, do 
they not indicate an abundance and a variety of these ani- 
mals during the upper secondary formations, as great as in 
any tropical region ? and have we not sufficient indications 
among the tertiarics to be justified in expecting that they 
also will turn out to be more numerous than they are now 
known to be! 
The class of Birds seems to form an exception in this view. 
But there seems to be particular reason why the bones of 
birds should be more liable to destruction and decomposition 
_ than those of other vertebrata. And whoever has traced the 
discoveries made recently among the fossils of this class, 
will certainly not insist upon a supposed scarcity of birds in 
former periods, but rather be inclined to admit that the li- 
mited number now known is to be ascribed to the deficiency of 
our knowledge rather than to a want of these animals in 
earlier formations,—indications of their presence having been 
ascertained for several tertiary formations, for cretaceous de- 
posits, and even for deposits belonging to periods older than 
the chalk. 
