Review of Recent Geological Literature. 321 
There are two other features which this book possesses which 
give it a unique character. These consist of detailed directions for 
geological surveying, i. e., the how and what to observe, and the 
methods of making maps and sections. These are essential to the 
equipment of a field geologist. It is necessary that the field geolo- 
gist be expert in interpreting and expressing the significance of the 
topographic features. In the chapter on the "Economic aspects of 
Geological Structure" is a thorough discussion of underground water. 
"This handbook addresses itself," as the author states in the 
preface, "in the first place to beginners in field geology, but I hope 
it may be found useful also to students who are preparing for pro- 
fessions in which some knowledge of Structural Geology is of prac- 
tical importance." It is not therefore a handbook for the experi- 
enced geologist, dealing with geological problems, and investiga- 
tions up to date. It only summarises the recognized fundamentals of 
geology. N. H. W. 
Economic Geology ot the United States, Heinrich Ries, Asst. Pro- 
fessor of Economic Geology at Cornell University, pp. xxi, 435; 
plates 26; fig. 97. The Macmillan Company, New York, 1905. 
Price $2.60, net. 
This work, which is intended to serve as an elementary text- 
book for students of economic geology, treats of the mode of occur- 
rence, distribution and uses of both the non-metallic and the metallic 
minerals and rocks in the United States which are of economic value. 
The book is divided into two parts: Part I. treating the non- 
metallic minerals, and Part II. the metallic minerals. This arrange- 
ment, which is perhaps different from that usually followed, has 
been adopted, because the non-metallic minerals produced annually 
have a greater aggregate value, and also for the reason that this 
line of discussion leads from the simpler to the more difficult part 
of the subject. 
Although an elementary work, the book contains also extensive 
lists of reference so that those desiring to pursue the subject further 
can do so. These references are grouped at the end of each chapter 
where they can be easily referred to by those needing them, but at 
the same time, by this arrangement they take up but little space in 
the book. 
In treating each mineral the aim has been to discuss its general 
characters and economic value, followed by a description of a few 
localities which are of importance or may serve as types, rather 
than to give a mass of detailed descriptions, which often tend 
simply to confuse the student. 
The difficult task of presenting in one volume of moderate size 
a description of the mineral resources of the United States, and of 
allotting to each subject the proper amount of attention, has been 
unusually well performed. The space given to non-metallic min- 
erals covers 215 pages, while 194 pages are devoted to metallic ores 
