Stereotyped by
HOBART & ROBBINS,
BOSTON.
PRESS OF G. C. RAND, CORNHILL, BOSTON.
PREFACE
In preparing the following work, it was intended to present a systematic and somewhat complete statement of the principles of Geology, within such limits that they may be thoroughly studied in the time usually allotted to this science.
A sufficient number of leading facts has been introduced to enable the learner to feel that every important principle is a conclusion to which he has himself arrived; and yet, for the purpose of compression, that fullness of detail has been avoided with which more extended works abound. In furtherance of the same object, authorities are seldom cited.
The consideration of geological changes is made a distinct chapter, subsequent to the one on the arrangement of materials. It should, however, be remembered that these processes of arranging and disturbing are not thus separated in time. In nature the two processes are always going on together.