Chapter I—on the Different Classes of Rocks.

Geology defined. — Successive Formation of the Earth’s Crust. — Classification of Rocks according to their Origin and Age. — Aqueous Rocks. — Their Stratification and imbedded Fossils. — Volcanic Rocks, with and without Cones and Craters. — Plutonic Rocks, and their Relation to the Volcanic. — Metamorphic Rocks, and their probable Origin. — The term Primitive, why erroneously applied to the Crystalline Formations. — Leading Division of the Work.