inquiry
into past natural events whose vastness puts them quite beyond the
resources of the laboratory. This method finds its key in a search for
the history of such vast and remote events by a scrutiny of the
vestiges these events have left as their own automatic record. This
method stands in sharp contradistinction to simple speculation without
such search for talismanic vestiges, a discredited method which is too
often supposed to be the only way of dealing with such themes. To be
really competent in the field of larger and deeper thinking, every
courageous mind should be able to cross the threshold of any of the
profound problems of the universe with safe and circumspect steps,
however certain it may be that only a slight measure of penetration of
the problem may be attainable. A well-ordered mind will remain at once
complacent and wholesome when brought to the limit of its effort by
the limit of evidence. The problem of the origin of celestial worlds,
of which the genesis of the earth is the theme of largest human
interest, is admirably suited to give college students at once a
modest sense of their limitations and a wholesome attitude toward
problems of the vaster type. Without having acquired the power to make
prudent and duly controlled excursions into the vaster fields of
thought, the mind can scarcely be said to have been liberalized.

=Geology a means of training in thinking in scientific experiences=

From the very outset, the tracing of the earth history forces a
comprehensive study of the co-workings of the three dominant states of
matter massively embodied in the atmosphere, the hydrosphere, and the
lithosphere, the great terrestrial triumvirate. The strata of the
earth are the joint products of these three elements and constitute
their lithographic record. These three cooperating and contending
elements not only bring into view the three typical phases of physical
action, but they present this action in such titanic aspects as to
force the young mind to think along large lines, with the great
advantage that these actions are controlled by determinate laws, while
the causes and the results are both tangible and impressive.

While there is a large class of tangible and determinate problems of
this kind, embracing shiftings of matter on the earth's surface,
distortions of strata, and changes of bodily form, there are also
problems of a more hidden nature such as internal mutations. These
give rise to ma