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.