REVIEWS.—THE STUDY OF ROOKS, ETO. 155 
Arcbietus. 
The Study of Rocks. By Franx Rurtry, F.G.S. London: Longmans, 
Green, and Co. 
This is a new volume of Messrs. Longmans’ well-known cheap series of 
«‘Text-Books of Science.” Mr. Rutley is petrologist to the Government 
Geological Survey, and in the book now before us he supplies a want 
much felt by English geologists, viz., a thorough and correct introduction 
to the study of rocks. To be able to recognise and correctly describe 
rocks, at all events any which we shall be likely to meet with in this 
country, is a power which must be diligently sought after by every student 
of geology. Such a knowledge, we have no hesitation in saying, can 
neither be aquired from books alone nor from specimens alone, but any 
one who will combine the two, who will carefully study Mr. Rutley’s 
work, while at the same time he examines collections of rocks and 
minerals, such as may be seen in any public museum, or obtained by 
exchange, or purchased from dealers, cannot fail to lay the foundation of 
a sound practical knowledge of this subject, which will be of great value 
to him at every succeeding step in the science of geology. In the intro- 
ductory chapters of this book Mr. Rutley gives, in a clear and concise 
manner, an account of the structure and phenomena of rock masses. 
He then gives very valuable and practical information on the formation 
of a rock collection, and on the examination of rocks, especially by the 
aid of the microscope. This part concludes with an account of the prin- 
cipal rock-forming minerals, their megascopic and microscopic characters. 
In Part II. the author describes the several species of rocks under two 
main heads—Eruptive and Sedimentary. This portion of the work is 
especially interesting, as it contains the latest, and, indeed, new, inform- 
ation on many points of interest and importance. This portion of the 
book would bear much amplification, so that in future editions (which 
will certainly be called for) the descriptive petrology might well form a 
second yolume. Altogether, it is certain that all practical workers in 
geology will hail as a great boon the appearance of this book, for it fills 
a distinct gap in the (English) literature of the science, whilst we may 
further hope that it will promote clearness of ideas and uniformity of 
nomenclature. 
W. J. 4H. 
The Post-Tertiary Deposits of Cambridgeshire. By A. J. Juxes-Browne, 
B.A., F.G.S. Cambridge: Deighton, Bell, and Co. 
Tus work is the Sedgwick Prize Essay for 1876. It constitutes an 
interesting and important contribution to the study of one of the 
‘‘burning” geological questions of the day—the origin, nature, and 
classification of the deposits of the Glacial Period. In the first two 
chapters Mr. Jukes-Browne furnishes a history of the work already done 
in this direction, both generally (chap. I.) and in the county of Cambridge, 
(chap. Il.) He next briefly denotes the physical features of the county, 
and then enters more fully into an account of the Great Chalky Boulder 
