332 
THE GEOLOGIST. 
REVIEWS. 
Illustrated Index of Brithh Shells, eo)daining figures of all the recent species, 
with names and other inforniution. By G. B. Sowekby, F.L.S. Loudon : 
Simpkin, Marshall and Co., 1859. 
The magnificent work on British shells by Mr. Hanlcy and the late Professor 
Forbes, must remain, for a long time at least, the standard book on British 
nioUusca. Its price, amounting to some ptninds, however, is a barrier to its 
being more extensively accessible, while there are thousands of inquiring minds 
V ho desire some reliable source from which, by comparison of the shells they 
fiud with some good figure, they can at least recognize a species, and thus find 
some lirm foundation on which to continue their investigations. Such a source 
is Mr. Sowerby's book, although it is little more than an illustrated catalogue 
of our native shells. The ii"-ui'es are very good, and appear to be original 
representations of properly selected specimens ; no slight consideration, for our 
attention has been often drawn to the evU effects of the practice of copying 
from other plates, in presenting false ideas, by depaitures from the original and 
proper outlines of the object thus occasioned, the errors of the draughts- 
man, often rendering the determination of species dithcult and obscure, and 
otherwise impeding the progress of science. We rejoice that Mr. Sowerby's 
book has passed well through our scrutiny on this point, and that we can con- 
sistently wish it the extensive sale it merits. 
Advanced Text Book of Geology, Descriptive and Industrial. By David Page, 
F.G.S. Second edition, revised and enlarged. London and Edinburgh : 
William Blackwood and Son. 1859. 
This treatise, the first edition of which, so well known, is reported to have 
sold to the extent of twenty thousand copies, was designed as a sequel to the 
author's " Introductory Text Book," although it has been prepared in such a 
manner as to stand also as a separate and independent work. The latter or 
introductory work gives an outline of the science intelligible to begiiuiers, and 
sufficient for a general acriuaintancc with its leading facts ; that under notice, 
or the "Advanced Text Book," presents the subject more in detail, and is "in- 
tended for senior pupils and those who desire to prosecute the study in its 
principles as well as deductions." 
The author's views are good of a right system of teaching ; and no geological 
book for scholastic pur])oscs in the English language surpasses Mr. Page's in 
this respect ; nor is the carefulness dispLayed in the correctness of the general 
material of the work to be passed over without laiidatory comment. 
This second edition has been enlarged, "firstly, to embrace whatever is new 
and important in the science ; secondly, to afford space for additional illustra- 
tion ; and thirdly, to combine, as far as possible, the principles with the de- 
ductions of the geology." 
This additional matter is ordinarily given " in subordinate type and in such a 
form as not to interfere with the continuity of the origuial textual arrange- 
ment." So far so good; and the matter thus introduced is certainly not witli- 
out nuich value, but we caution agamst incrcasmg the dimensions of a Text 
Book. It is, in our opinion, dangerous both to its practical and to its pecuniary 
success ; while it is desirable for its attractiveness to the student — no mean 
consideration — to restrain it within the most moderate limits. 
