64 
SCIENTIFIC LITERATURE. 
The Ancient Volcanoes of Great Britain. By Sir 
ARCHIBALD GEIKIE. London, Macmillan 
& Co., Limited. New York, The Mac- 
millan Company. 1897. 2 vols., Imperial 
8yo, with seven maps and many illustra- 
tions. 
The title of this work is hardly commensurate 
with the scope of its subject-matter. Since the 
author’s characteristic modesty has restrained 
him from giving it a name adequately express- 
ing its magnitude and importance, he may 
kindly permit his readers to name it for him in 
full and call it more justly: A treatise on vul- 
canology exemplified chiefly by the ancient 
volcanoes of Great Britain. Such a treatise is 
needed. The time is come when the cumula- 
tive gains of our knowledge of volcanoes ac- 
quired during the last twenty years should be 
reckoned up and an account of stock taken, 
when bad assets should be sponged out and 
doubtful ones appraised at reasonable estimates. 
Nearly every branch of science needs a periodic 
overhauling and a revised statement of its 
general facts and principles in the light of its 
most recent advances. It is long since volcanic 
geology has had a satisfactory one. But it has 
one now at the hands of a master. The method 
of treatment, the logical order of the constitu- 
ent parts, the arrangement of its wealth of 
material, are such as to enable the reader to see, 
as clearly as the present state of the science per- 
mits, the relations of parts to the whole and of 
facts to principles. The broader generalizations 
which have thus far been reached concerning 
the nature of volcanic action, its products and 
their modes of occurrence, are first stated. They 
are put forward briefly and conservatively, and 
no words are wasted in needless discussion. 
This presentation of the subject of vulecanism 
in general is the object of the first seven chap- 
ters, or Book I. The remainder of the work 
is a detailed discussion of the volcanic phe- 
nomena of the British Islands. The arrange- 
ment or plan of this discussion is doubtless the 
best one that could be selected. It begins with 
the most ancient, advances through the succeed- 
ing geological ages in their regular order, and 
ends with the most recent. The broader and 
more general facts laid down in Book I. are the 
SCIENCE. 
[N.S. Vou. VI. No. 132. 
guiding principles of this discussion, and the 
vast array of concrete facts becomes the founda- 
tion upon which the principles and generaliza- 
tions repose. It will be interesting to glance, 
necessarily in the briefest manner, at the special 
points of interest in this work. 
The first chapter is in the nature of a prelude 
or exordium preparatory for what is to follow. 
It points out what geologists of other countries 
might otherwise fail to realize, that the British 
Islands have peculiar advantages for this study 
because of the remarkable completeness of the 
geological record, the exceptionally full de- 
velopment of volcanic activity in nearly all 
geological ages, and the advantageous man- 
ner in which its results are exposed to view 
by denudation. American geologists may 
find difficulty at first in realizing this, but 
the author makes it certain. And so this 
little island, which would be buried half a 
mile deep in a fraction of the laya which 
swamps our northwestern States, proves to be 
as fruitful in material for the edification of vul- 
canology as it has been for the advancement of 
civil liberty and civilization. In the work at 
large we find such a wide range and variety of 
volcanic phenomena that the rest of the world 
is not likely to furnish many that are much 
more valuable, or that would materially affect 
the inductions drawn from those of Britain, 
though other regions may furnish occurrences 
which seem to be absent there. 
The second chapter speaks of the causes of 
volcanic action. It is, therefore, a very short 
one, for alas! how little we know of those 
causes. Just here we are fortunately not con- 
cerned with the discussion of them, but merely 
with the way in which the author treats them. 
He says just enough to indicate his acquiescence 
in the contractional hypothesis, of which the 
extrusion of molten magmas within the earth 
is regarded as a concomitant. Conjoined with 
this is the intense elastic or explosive force of 
the vapors occluded in those magmas and which 
we see escaping from them during the act of 
eruption. The causes of volcanic action consti- 
tute the darkest and most discouraging problem 
in physical geology, with the exception of the 
causes of regional elevations, which may per- 
haps be only another phase of the same mystery. 
