[Oftobei*, 
54 6 Notices of Books. 
always been one of law. Yet Catastrophism overlooks this fun- 
damental fadt. It is curious to look back to the assumptions 
devised by Catastrophists and Brachychronologists to explain 
away the evidence of the earth’s past. Thus Sir David Brewster, 
whilst fully admitting the traditional longevity of antediluvian 
man, suggested — to account for the formation of the coal-strata 
within the six thousand years of what was once the received 
chronology- — that organic life was “ once upon a time ” briefer 
and more rapid than it is now, and that whole forests might have 
sprung up to maturity and passed away in fewer years than they 
would now require centuries.” This introductory sedtion of the 
present work may be most advantageously studied, even by those 
who may feel no special interest in the details to follow. 
As regards the body of the work, space will not allow us to 
examine it minutely, chapter by chapter. The fadts adduced 
are, of course, to a great extent the common property of geolo- 
gists. But even the veriest tyro must, we should think, feel that 
he is under the guidance not of a compiler stringing together the 
most interesting — we had almost said the most sensational — 
matter upon which he has stumbled whilst “ reading up ” the 
subjecft, but of a master in the science who understands the 
significance of every phenomenon which he records, and knows 
how to make it reveal its lessons. 
The cautions given concerning the possible sources of error 
in palaeontological inquiry are well worthy the attention of the 
student. Dr. Nicholson reminds us of the frequent absence of 
fossils in stratified rocks ; of the confusion caused by observers 
in different parts of the world giving different names to one and 
the same fossil, or, conversely, “lumping” distinCt fossils under 
some common name. These errors are naturally dangerous 
whenever we argue as to the comparative age of strata from the 
presence of certain fossil remains. He further shows that the 
mere faCt of a difference of physical position cannot safely be 
taken into account in determining the true zoological affinities of 
a fossil. Unsafe, also, is the inference that all beds containing 
similar fossils must be of the same age. The palaeontologist 
may also be led astray by accepting obscure or imperfedt physical 
evidence as to the age and position of some given group of 
strata. 
Concerning the inferences drawn from fossil remains as to the 
former climate of the locality where they are found, some im- 
portant cautions are given. The author points out that, as fossils 
are mostly the remains of marine animals, the evidence obtained 
bears chiefly upon the temperature of the seas, which, from the 
existence of currents, hot or cold, does not necessarily prove a 
corresponding temperature in the adjacent lands. It is, more- 
over, by no means certain that the “ habits and requirements ” 
of any extindt animal were exadtly the same as those of its 
nearest living representatives. Nor is the distribution of species 
