■ 
CONTENTS. 
CHAPTER I. 
ON THE DIFFERENT CLASSES OF ROCKS. 
Geology defined.—Successive Formation of the Earth’s Crust.—Classifica¬ 
tion 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. .Page 25 
CHAPTER II. 
AQUEOUS ROCKS—THEIR COMPOSITION AND FORMS OF STRATIFICATION. 
Mineral Composition of Strata.—Siliceous Rocks.—Argillaceous.—Calcare¬ 
ous.—Gypsum.—Forms of Stratification.—Original Horizontality.—Thin¬ 
ning out.—Diagonal Arrangement.—Ripple-mark. 35 
CHAPTER III 
ARRANGEMENT OF FOSSILS IN STRATA—FRESH-WATER AND MARINE. 
Successive Deposition indicated by Fossils.—Limestones formed of Corals 
and Shells.—Proofs of gradual Increase of Strata derived from Fossils.— 
Serpula attached to Spatangus.—Wood bored by Teredina.—Ti ipoli form¬ 
ed of Infusoria.—Chalk derived principally from Organic Bodies.—Dis¬ 
tinction of Fresh-water from Marine Formations.—Genera of Fresh-water 
and Land Shells.—Rules for recognizing Marine Testacea.—Gyrogonite 
and Chara.—Fresh-water Fishes.—^Alternation of Marine and Fresh-water 
Deposits.—Lym-Fiord. 47 
CHAPTER IV. 
CONSOLIDATION OF STRATA AND PETRIFACTION OF FOSSILS. 
Chemical and Mechanical Deposits.—Cementing together of Particles.— 
Hardening by Exposure to Air.—Concretionary Nodules.—Consolidating 
Effects of Pressure.—Mineralization of Organic Remains.—Impressions 
and Casts : how formed.—Fossil Wood.—Goppert’s Experiments.—Pre¬ 
cipitation of Stony Matter most rapid where Putrefaction is going on.— 
' Sources of Lime and Silex in Solution. 60 
