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POPULAR SCIENCE REVIEW. 
recent discoveries. To be sure, Lyell’s “Student’s Elements” exists, but 
then that is more a general manual of geology and palaeontology. If we 
except this one work, which, as we have had occasion before to say, is an 
admirable one, abundantly illustrated, we may be said to have been des- 
titute of students’ manuals of palaeontology for the past ten years. We 
certainly do not see why it should have been so, but unquestionably we 
have not had a full work on fossils devoted exclusively to the student’s 
wants for many years. Dr. H. A. Nicholson has, therefore, rather an 
empty field in which to display his merits, for assuredly there are no can- 
didates to oppose him. This volume is one of 8vo. size, and of nearly 600 
pages. It is admirably illustrated, having over 400 woodcuts many of which 
are excellently executed ; but the author has been unhappy in his selection 
of both type and paper, the former being of a size decidedly too small, 
and the latter being not white but of a sickly yellowish hue. But having 
said so much, we have most probably said the worst we shall have to say 
against the volumes. The author commences with a few chapters on the 
principles of palaeontology ; and in these we think he does himself credit for 
his calm admission of the difficulty of assuming that because rocks are simi- 
lar in appearance and structure, they are of contemporaneous origin. Dr. 
Nicholson shows, by reference to Dr. Carpenter’s researches, which he is quite 
prepared to admit, that this is one of the greatest difficulties of the geologic 
task. Nor is he ready to admit that identity of fossil remains indicates 
similarity of age of deposit, for he is well aware of the fact that, at the 
present moment, there are being developed huge formations in the Medi- 
terranean, the Atlantic, and the Pacific, which will one day see the light as 
rocks, unquestionably the same, in point of time, yet as different both in 
composition and fossils as it is possible to conceive. We admire, then, the 
manner in which Dr. Nicholson has dealt with these questions. In the 
generality of instances, he cites from the most eminent and recent authorities ; 
and he gives the student ample materials for forming an opinion, without 
binding him to any special theory in cases where two or three views may 
exist and have a good deal of support. 
The next part of his work is unquestionably the most important, and 
there is but one point we have to object to — that is, to the term palaeonto- 
logy as applied to animals alone. In our opinion, palaeontology should be 
a generic expression, having two specific names included within it. This, 
however, though adopted in the work itself, is not adopted in the author’s 
preface, for herein he speaks of the animal remains found fossil forming the 
branch of Pol<^ontology, and the plant-remains being properly called Palceo~ 
hotany. However, in the work itself he has the two specific names rightly 
placed — Palceozoology and Palceohoiany. In the several chapters which he 
has devoted to palaeozoology, we find that he has followed a tolerably recent 
classification of the animal kingdom, and that in each case sub-kingdom, 
class, and order are clearly defined. Of course, we could find fault with the 
definitions in many cases, but we are aware that that is a condition that 
may be said for every classification on earth ; for there is hardly any system 
which, if defined literally, will include every animal placed within it. 
But, on the whole, Dr. Nicholson has framed his definitions with terseness 
and comprehensiveness, and in nearly all cases his classes are placed in their 
