thematical, physical, and chemical inquiries while at
the same time they call into play the use of the scientific
imagination and are thus rich in the possibilities of training. Thus
in varied ways geological work joins hands with chemical, physical,
mechanical, and mathematical work.

When life first appears in the record, there is occasion to raise the
profound question of its origin, and with this arises a closely
related question as to the nature of the conditions that invited life,
which leads on to the further question, what fostered the development
of life throughout its long history? While the obscurity of the
earliest record leaves the question of origin indeterminate for the
present, duly guarded thought upon the subject should foster a
wholesome spirit toward inquiry in this vital line as well as a
hospitable attitude toward whatever solution may finally await us. In
all such studies the student should be invited to look to _the
vestiges left automatically by the process itself_ for the answer, and
he should learn to accept the teachings of evidence precisely as it
presents itself. So also when a problem is, for the present,
indeterminate, it is peculiarly wholesome for the inquirer to learn to
rest the case where the light of evidence fails, and to be complacent
in such suspension of judgment and to wait further light patiently in
serene confidence that the vestiges left by the actuating agencies in
their constructive processes are the surest index of the ultimate
truth and are likely to be sooner or later detected and read truly.

=Relation of geology to botany, zoology, psychology, and sociology=

In the successive records of past life impressed on strata piled one
upon another until they form the great paleontologic register, there
is an ample and a solid basis for the study of the historic evolution
of life. With this also go evidences of the conditions that attended
this life progress and that gave trend to it. This record of the
relations of life to the environing physical conditions forms one of
the most stimulating fields of study that can engage the student who
seeks light on the great problems of biological progress. Here geology
joins hands with botany and zoology in a mutual helpfulness that is
scarcely less than indispensable to each.

Following, or perhaps immediately attending, the introduction of
physiological life, there appeared signs of sentient life. The
preservation of certain of the