vill PREFACE 
With structural and dynamic geology the case is some- 
what different. Here the body of fact necessary for ele- 
mentary understanding is not so great nor so difficult to- 
grasp. The teachings of these truths of geology are illus- 
trated on every hand, and, in fact, some of them are already 
familiar to the pupil before he enters upon the study. They 
deal with phenomena in the midst of which we dwell, and 
hence should become a part of the mental possessions of 
every high school pupil. I believe that these aspects are 
preéminently suited to become a part of the secondary school 
curriculum. 
The second reason for putting forth the book is to furnish 
a companion and adjunct to my Elementary Physical Geog- 
raphy. Parts of this need explanation and amplification, 
such as a Geology can give. Moreover, I believe that a year 
given to the combined study of the two subjects will furnish 
a training in science which will be of great value. The 
study of the land, as covered in physical geography of the 
modern school, needs to be preceded by a knowledge of geol- 
ogy, and it is my hope that the study of this will be intro- 
duced into the schools. Really this land study is a part of 
geology, and hence, though the titles of the books are differ- 
ent, there would be no real break in the treatment if, after a 
study of air and ocean, geology is taken up, and this be 
followed by the study of physiography or physiographic 
geology. In these studies I would urge most strongly the 
advisability of laboratory and field work, whenever and 
wherever possible. 
