Geology is of all "hobbies" the one best calculated not only to develop
the physical powers, but also, if pursued with any degree of
earnestness, to train and extend the mental faculties. To study geology
properly, the rocks themselves must be visited and carefully observed,
their appearance noted, and the fossils, if any, which they contain,
collected. This necessitates many a pleasant walk into the open country
to quarries and cuttings, or rambles along the sea-shore to cliffs which
may be worth investigating, whilst botany, entomology, or any other
congenial pursuit, may be followed on the way; for natural science in
its different branches has so many points of connection that it is
impossible to study one of them without increasing one's interest in,
and knowledge of, all the others. Again, in arranging, classifying, and
studying at home the specimens collected on these expeditions, many an
hour may be usefully spent; habits of exactitude and neatness are
acquired; whilst in endeavouring to draw correct conclusions as to the
way in which particular rocks were formed, and by what agencies brought
to their present position, the reasoning faculties are exercised and
developed.
The existence of fossil shells and bones in various strata of the
earth's crust attracted attention at a very early date of the world's
history; the Egyptian priests were aware of the existence of marine
shells in the hills bounding the Nile valley, and from this fact
Herodotus drew the conclusion that the sea formerly covered the spot.
The bones of the larger mammalia (rhinoceros, elephant, etc.), were,
however, thought by the ancients to be human, and hence arose the idea
of a race of giants having existed at some previous period of the
earth's history. It was not, however, until near the end of the last
century that geology began to be recognised as a science, and the true
bearing of fossils in relation to the rocks in which they were found was
conclusively proved. William Smith in England, and Werner in Germany,
while working independently of each other, both came to the same
conclusion, viz. that the numerous strata invariably rested on each
other in a certain order, and that this order was never inverted,[1]
whilst William Smith in addition proved that each group of rocks, and
even each stratum, had its own peculiar set of fossils, by which it
might be recognised wherever it occurred. From that time forth the study
of the various fossils began to be considered as a separate science
apart from that of the beds containing them; this is now known as
Palaeontology, the study of the composition of the rocks themselves being
termed Petrology.
[1] Except in such cases where the rocks themselves have been
displaced by movements of the earth's crust.
At this moment, however, we are less concerned with the study of rocks
and fossils than with the best and simplest way of collecting,
preparing, and arranging specimens as a means to this study.