Notices of Books . 
545 
1876.] 
methods which can be carried out in the field with the minimum 
of appliances. The student who follows his directions, and who 
has duly prepared himself by a careful study of cabinet speci- 
mens of the ordinary rocks and minerals, will soon feel at home 
in this department of geology. The author reverses the process 
often directed ; he tabulates the results obtainable, and from 
them deduces the nature of the rock in question. The exami- 
nation to which he subjects rocks in the field consists of noting 
the texture, fraCture, lustre, behaviour with knife, effervescence 
with dilute acid, colour, and streak, the inferences drawn from 
these indications being afterwards verified at home by a deter- 
mination of the hardness, specific gravity, solubility, and 
behaviour before the blowpipe. The examination of thin slices 
of rock under the microscope — of course impracticable in the 
field — is strongly and very justly recommended. 
In the section on palaeontology — the first three chapters of 
which are from the pen of Mr. jukes- Browne — we meet with a 
remark which we would commend to the attention of those who 
are given to complain of the absence of “ missing links — 
“ Since the majorit}' of rocks composing the crust of the earth 
are of aqueous and principally marine origin, we should naturally 
expeCt the fossils they contain to be the remains of aquatic and 
principally marine beings. Thus, in the Vertebrata, the remains 
of mammals and birds are among the rarest of geological relics, 
even in beds of littoral or terrestrial origin, save those of very 
recent date.” This plain simple truth fully exposes the absurdity 
of drawing any conclusions from the absence of this or the other 
form of extinCt life in the strata which we have been able to 
examine. The instructions given for collecting fossils bear the 
marks of experience and sound sense. The following “wrinkle” 
may be of value to the student : — “ Chalk-fossils, and those 
which have been obtained from any similar porous limestone 
along the sea-shore, should be soaked in fresh water for several 
weeks, the water being changed at least once a week : this is the 
only way we know of to prevent the efflorescence of the salt in 
such cases, and the consequent splitting up of fossils which 
have cost time and pains to extraffl.” 
We find some very just remarks on the naming and arranging 
of fossils. The author laments the illusory ideas regarding the 
fixity of species, and the too great desire of finding something 
new to science “ which too often takes the form of species-making 
instead of discovery .” For this tendency he considers that “the 
only cure is to read Darwin’s ‘ Origin of Species,’ and persons 
who will not do that may be given up as hopeless.” 
We can decidedly recommend this work to the student as sup- 
plying a want of no mean importance. 
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VOL. VI. (N.S.) 
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