The Elements of Geology | Page 4

work, however, is the outcome of the need of a
text-book of very simple outline, in which causes and their
consequences should be knit together as closely as possible,--a need
long felt by the author in his teaching, and perhaps by other teachers
also. The author has ventured, therefore, to depart from the common
usage which subdivides geology into a number of
departments,--dynamical, structural, physiographic, and historical,--and
to treat in immediate connection with each geological process the land
forms and the rock structures which it has produced.
It is hoped that the facts of geology and the inferences drawn from
them have been so presented as to afford an efficient discipline in
inductive reasoning. Typical examples have been used to introduce
many topics, and it has been the author's aim to give due proportion to
both the wide generalizations of our science and to the concrete facts
on which they rest.
There have been added a number of practical exercises such as the
author has used for several years in the class room. These are not made
so numerous as to displace the problems which no doubt many teachers
prefer to have their pupils solve impromptu during the recitation, but
may, it is hoped, suggest their use.

In historical geology a broad view is given of the development of the
North American continent and the evolution of life upon the planet.
Only the leading types of plants and animals are mentioned, and special
attention is given to those which mark the lines of descent of forms
now living.
By omitting much technical detail of a mineralogical and
paleontological nature, and by confining the field of view almost
wholly to our own continent, space has been obtained to give to what
are deemed for beginners the essentials of the science a fuller treatment
than perhaps is common.
It is assumed that field work will be introduced with the
commencement of the study. The common rocks are therefore briefly
described in the opening chapters. The drift also receives early mention,
and teachers in the northern states who begin geology in the fall may
prefer to take up the chapter on the Pleistocene immediately after the
chapter on glaciers.
Simple diagrams have been used freely, not only because they are often
clearer than any verbal statement, but also because they readily lend
themselves to reproduction on the blackboard by the pupil. The text
will suggest others which the pupil may invent. It is hoped that the
photographic views may also be used for exercises in the class room.
The generous aid of many friends is recognized with special pleasure.
To Professor W. M. Davis of Harvard University there is owing a large
obligation for the broad conceptions and luminous statements of
geologic facts and principles with which he has enriched the literature
of our science, and for his stimulating influence in education. It is
hoped that both in subject-matter and in method the book itself makes
evident this debt. But besides a general obligation shared by geologists
everywhere, and in varying degrees by perhaps all authors of recent
American text- books in earth science, there is owing a debt direct and
personal. The plan of the book, with its use of problems and treatment
of land forms and rock structures in immediate connection with the
processes which produce them, was submitted to Professor Davis, and,
receiving his approval, was carried into effect, although without the

sanction of precedent at the time. Professor Davis also kindly
consented to read the manuscript throughout, and his many helpful
criticisms and suggestions are acknowledged with sincere gratitude.
Parts of the manuscript have been reviewed by Dr. Samuel Calvin and
Dr. Frank M. Wilder of the State University of Iowa; Dr. S. W. Beyer
of the Iowa College of Agriculture and Mechanic Arts; Dr. U. S. Grant
of Northwestern University; Professor J. A. Udden of Augustana
College, Illinois; Dr. C. H. Gordon of the New Mexico State School of
Mines; Principal Maurice Ricker of the High School, Burlington, Iowa;
and the following former students of the author who are engaged in the
earth sciences: Dr. W. C. Alden of the United States Geological Survey
and the University of Chicago; Mr. Joseph Sniffen, instructor in the
Academy of the University of Chicago, Morgan Park; Professor Martin
Iorns, Fort Worth University, Texas; Professor A. M. Jayne, Dakota
University; Professor G. H. Bretnall, Monmouth College, Illinois;
Professor Howard E. Simpson, Colby College, Maine; Mr. E. J. Cable,
instructor in the Iowa State Normal College; Principal C. C. Gray of the
High School, Fargo, North Dakota; and Mr. Charles Persons of the
High School, Hannibal, Missouri. A large number of the diagrams of
the book were drawn by Mr. W. W. White of the Art School of Cornell
College. To all these friends, and