his higher probability; or if they have
reached it, have dreaded the scorn of the half-learned too much to
utter their convictions. Still this is a position which the
enlightened Christian and student of nature must be prepared to
occupy, humbly and with admission of much ignorance and incapacity,
but with bold assertion of the truth that there are meeting-points of
nature and revelation which afford legitimate subjects of study.

In entering on these subjects, we may receive certain great truths in
reference to the history of the earth as established by geological
evidence. In the present rapidly progressive state of the science,
however, it is by no means easy to separate its assured and settled
results from those that have been founded on too hasty generalization,
or are yet immature; and at the same time to avoid overlooking new and
important truths, sufficiently established, yet not known in all their
dimensions. In the following summary I shall endeavor to present to
the reader only well-ascertained general truths, without indulging in
those deviations from accuracy for effect too often met with in
popular books. On the other hand, we have already found that the
Scriptures enunciate distinct doctrines on many points relating to the
earth's early history, to which it will here be necessary merely to
refer in general terms. Let us in the first place shortly consider the
conclusions of geology as to the origin and progress of creation.

1. The widest and most important generalization of modern geology is
that all the materials of the earth's crust, to the greatest depth
that man can reach, either by actual excavation or inference from
superficial arrangements, are of such a nature as to prove that they
are not, in their present state, original portions of the earth's
structure; but that they are the results of the operation, during long
periods, of the causes of change--whether mechanical, chemical, or
vital--now in operation, on the land, in the seas, and in the interior
of the earth. For example, the most common rocks of our continents are
conglomerates, sandstones, shales, and slates; all of which are made
up of the debris of older rocks broken down into gravel, sand, or mud,
and then re-cemented. To these we may add limestones, which have been
made up by the accumulation of corals and shells, or by deposits from
calcareous springs; coal, composed of vegetable matter; and granite,
syenite, greenstone, and trap, w