REVIEWS 
THE STUDY OF ROCKS.* 
T HIS book well supplies a want long felt by students of Petrology in this 
country. Several valuable text-books on the subject have within the 
last few years been published on the Continent, but Mr. Rutley’s volume is 
the first purporting to afford elementary instruction on the study of rocks 
by the aid of the microscope, which has appeared in the English language. 
The work is divided into two parts — Rudiments of Petrology, and 
Descriptive Petrology. 
Beginning with a chapter on methods of petrological research, the 
author proceeds to consider the origin of rock-masses and of the various 
disturbances to which the earth’s crust has been subjected, as well as the 
general characters and modes of occurrence both of eruptive and sedimentary 
rocks. 
A minute description is given of the appliances and methods employed for 
the preparation of sections suitable for microscopical examination, as well as 
of the microscope and accessories best suited for this class of investigation. 
A chapter follows on the examination of the optical characters of thin 
sections of minerals ; and the first division of the work terminates with a 
lucid description of the principal rock-forming minerals, including both 
their megascopic and microscopic characters. 
The second division, which is devoted to a description and classification 
of the various eruptive and sedimentary rocks, affords evidence of much 
careful consideration, and furnishes a fair epitome of the present state of 
our knowledge of this subject. 
The text is illustrated by a large number of woodcuts, which, although 
not elaborate, are always clear and effective. A few slight oversights of a 
kind incident to all first editions have been observed, but the book is gene- 
rally characterised by clearness and accuracy. It will therefore be welcomed 
by all who may wish to acquire a competent knowledge of Petrology, but 
more particularly by those unacquainted with German and Erench, in which 
languages all previously available works on this subject have been written. 
From its somewhat limited extent, certain subjects have of necessity 
received but small attention, although nothing of importance appears to 
have been omitted. We therefore heartily recommend Mr. Rutley’s volume 
* u The Study of Rocks, an Elementary Text-book of Petrology.” By 
Frank Rutley, Esq., F.G.S., H.M. Geological Survey. London : Longmans, 
1879. 
