DESIGNED FOR THE USE OF SCHOOLS AND GENERAL READERS.

BY J. L. COMSTOCK, M. D.
Author of an Introduction to Mineralogy, Elements of Chemistry, A System of
Natural Philosophy, and Introduction to Botany.

PREFACE.

GEOLOGY is peculiarly adapted to impress the mind of the student with ideas of the wisdom and power of the Creator, and to lead him to the acknowledgment of a Great First Cause. In addition to this, it is applicable to various, and highly important practical purposes. Millions have been expended in boring for salt, in mining for coal, and in searching for metallic veins, when even a slight knowledge of the nature and geological positions of rocks, as indicated by external appearances, would have shown that such explorations would be fruitless.

In the sinking of wells, in excavations for canals, roads, and buildings, and for a great variety of other purposes connected with both civil and military engineering, a knowledge of geology is often of the highest importance to the contractor, and not less so to the contracting party.

Is it not time, then, that we should begin the study of the earth on which we live, and from which, in common with al terrene animals, we derive our subsistence? And can it be doubted, that the knowledge to be derived from this source, is fully as important to the youth of this great and unexplored country, as that pertaining to the names and sources of rivers, the extent and situation of seas, and the boundaries of nations, states, and towns, which our scholars spend so much time in committing to memory?

To supply the deficiency of books on this subject, adapted to general readers and to our higher schools, is the object of this work. Possibly the clergy of our country, who have no time to read extensive geological works, and thus to collect the scattered facts which show the coincidence and connexion between the Scriptures and geology, may find this little volume an acceptable assistance. At the present day, when infidelity looks almost exclusively among the higher departments of science for aid, ought not theologians, at least, to understand the ground of such hopes, in order to make good their own defence? An experienced soldier always looks well to the strength of his outposts.

With respect to the matter of the following treatise, it is perhaps sufficient to say, that almost every recent systematic geological writer in the English language, as well as many periodical publications, have been consulted. The plan has been to treat of the most interesting and important parts of the science, as a whole, and hence particular notices on American geology have been omitted, only in conformity to this design.

To those acquainted with the present state of geology, it hardly need be said, that to have prepared a volume which should embrace and unite the opinions of even the most recent and respectable authors on many subjects contained within its outlines, would have