106 Analysis of Scientific Books. 
the animals in question, and another to assign them truly to their 
geological situations. It is not sufficient that every fragment of bone, 
whether of land animals or of fishes, should be referred to an indi- 
vidual species or genus; but it is most essential that the true geologi- 
cal situations in which they occur, should be accurately understood 
and accurately described. We do not want to know merely what 
animals have existed, but when, where, and how they lived. .Doubt- 
less, it is important to know that many animals lived at all in a 
former state of the world, which are living in it no longer ; it is im- 
portant to know what these were, and how many ; what species and 
genera have disappeared. ‘This is a question however, which, ab- 
stractedly taken, concerns zoology only. The geologist is anxious 
for much more. He desires to know at what period of the globe 
they were in existence, in what lands or waters they lived, when they 
were buried and preserved, and how. And he desires to know all 
this, because he makes use of it as evidence respecting the history of 
the globe and its revolutions. Hence, he ascertains, or at least addu~ 
ces collateral evidence towards ascertaining, the nature, and order, 
and places, and comparative times of its revolutions; and thus he 
acquires knowledge which, judiciously combined with the history of 
the mere rocks themselves and their various phenomena, enable him 
to make nearer approximations to a true theory of the earth. 
It is indispensable therefore that the comparative anatomist should 
in this case be a practical, expert, judicious, and experienced geolo- 
gist. He should be as replete with sound logic as he is free of 
system; should be as accurate an observer of geological facts as well 
stored with observations ; and should be able, from his general know- 
. ledge, to exercise a critical and sound judgment on the reports and 
observations in zoology as in natural history, of those from whom he 
is compelled to borrow what he has not possessed the means of ascer= 
taining from personal observation. 
We wish we could say that Cuvier, much as we respect his sound- 
ness of mind and minute knowledge in comparative anatomy, were 
able equally to stand this test in geology. We wish we could say this 
in a far minor degree of Monsieur Blainville ; but he is no geologist. 
Judging from his book, we are entitled to say that he has as little 
knowledge of this important part of his duty as is well possible. 
He is no observer, and he cannot be a critic. Hence every thing 
from which the geologist ought to have derived assistance, all that 
he would have turned to for light, only leaves him in darkness, the 
same or worse than before. 
Monsieur Blainville copies, without discrimination, from the descrip- 
tion of those who wrote before geology had been rescued from its 
ancient state of night and chaos; and, unable or unwilling to verify or 
rectify the observations of his remote predecessors, leaves every 
thing where he found it, or rather, adds to the confusion which per- 
vades their remarks. 
