While the Astronomer is studying the form and condition and structure
of the planets, in so far as the eye and the telescope can aid him, the
Geologist is investigating the form and condition and structure of the
planet to which he belongs; and it is from the analogy of the earth’s
structure, as thus ascertained, that the astronomer is enabled to form
any rational conjecture respecting the nature and constitution of the
other planetary bodies. Astronomy and Geology, therefore, constitute
the same science--the science of material or inorganic nature.
When the astronomer first surveys the _concavity_ of the celestial
vault, he finds it studded with luminous bodies differing in magnitude
and lustre, some moving to the east and others to the west; while by
far the greater number seem fixed in space; and it is the business of
astronomers to assign to each of them its proper place and sphere, to
determine their true distance from the earth, and to arrange them in
systems throughout the regions of sidereal space.
In like manner, when the geologist surveys the _convexity_ of his
own globe, he finds its solid covering composed of rocks and beds of
all shapes and kinds, lying at every possible angle, occupying every
possible position, and all of them, generally speaking, at the same
distance from the earth’s centre. Every where we see what was deep
brought into visible relation with what was superficial--what is old
with what is new--what preceded life with what followed it.
Thus displayed on the surface of his globe, it becomes the business
of the geologist to ascertain how these rocks came into their present
places, to determine their different ages, and to fix the positions
which they originally occupied, and consequently their different
distances from the centre or the circumference of the earth. Raised
from their original bed, the geologist must study the internal forces
by which they were upheaved, and the agencies by which they were
indurated; and when he finds that strata of every kind, from the
primitive granite to the recent tertiary marine mud, have been thus
brought within his reach, and prepared for his analysis, he reads their
respective ages in the organic remains which they entomb; he studies
the manner in which they have perished, and he counts the cycles of
time and of life which they disclose.--_Abridged from the North-British
Review_, No. 9.