285 
REVIEWS. 
FIELD GEOLOGY.* 
F the many elementary treatises and text-hooks prepared for the geolo- 
gical student, scarcely any treat of the method of observation in the 
field, or if so, only in a very general way. The “ How to Observe,” by 
De la Beche, and the “ Guide du Geologue-Voyageur,” by A. Boue, contain 
many valuable suggestions bearing on the subject, and may still be con- 
sulted with advantage. A good practical work has been long a desideratum, 
and this is to a great extent supplied by the “Field Geology” of Mr. 
What to observe, how to observe, and how to record observations in the 
field, are important parts of geological study ; and all theoretical knowledge 
derived from hand-books by the student of geology, should if possible be 
supplemented, as in the medical curriculum, by clinical instruction and 
observation at the bedside. For one of the real objects of inquiry in the 
field is to understand, when examining a section in a quarry or a sea-cliff, 
the nature of the various beds, and the conditions under which they were 
accumulated. In these respects the chapters on Lithology and Palaeontology 
(chaps, iii. and iv.) will be of service, although the latter chapter might 
be corrected and improved ; a dry list of fossils, without a knowledge of 
their bearings, being of little use. 
The chapters devoted to geological mapping and sections form an im- 
portant part of the book, as these are essential elements in understanding 
the structure of a country. The operations and the means of carrying them 
out are clearly given by the author, and are accompanied by tables and plans 
which render the text clearer, especially as regards the drawing of boundary 
lines, a practical matter of considerable importance, instruction in which has 
been somewhat neglected. 
With this view the author first describes the necessary instruments used 
in field-surveying, and then proceeds in a very systematic and detailed 
manner to show their applications, and the methods by which the tracing of 
geological boundaries is effected and the construction of horizontal sections 
carried out ; as well as how errors may arise in the latter case if the 
* “ Field Geology.” By W. H. Penning, F.G.S. ; with a section on 
Palaeontology, by A. J. Jukes-Browne, B.A., F.G.S. Sm. 8vo. London: 
Bailliere, Tindall, & Cox. (No date.) 
Penning. 
