Aqueous and igneous rocks--General characters of the sedimentary rocks--Mode or formation of the sedimentary rocks--Definition of the term "formation"--Chief divisions of the aqueous rocks--Mechanically-formed rocks, their characters and mode of origin--Chemically and organically formed rocks--Calcareous rocks--Chalk, its microscopic structure and mode of formation--Limestone, varieties, structure, and origin--Phosphate of lime--Concretions--Sulphate of lime--Silica and siliceous deposits of various kinds--Greensands--Red clays--Carbon and carbonaceous deposits. CHAPTER III. Chronological succession of the fossiliferous rocks--Tests or age of strata--Value of Palæontological evidence in stratigraphical Geology--General sequence of the great formations. CHAPTER IV. The breaks in the palæontological and geological record--Use of the term "contemporaneous" as applied to groups of strata--General sequence of strata and of life-forms interfered with by more or less extensive gaps--Unconformability--Phenomena implied by this--Causes of the imperfection of the palæontological record. CHAPTER V. Conclusions to be drawn from fossils--Age of rocks--Mode of origin of any fossiliferous bed--Fluviatile, lacustrine, and marine deposits--Conclusions as to climate--Proofs of elevation and subsidence of portions of the earth's crust derived from fossils. CHAPTER VI. The biological relations of fossils--Extinction of life-forms--Geological range of different species--Persistent types of life--Modern origin of existing animals and plants--Reference of fossil forms to the existing primary divisions of the animal kingdom--Departure of the older types of life from those now in existence--Resemblance of the fossils of a given formation to those of the formation next above and next below--Introduction of new life-forms. PART II. HISTORICAL PALÆONTOLOGY. CHAPTER VII. The Laurentian and Huronian periods--General nature, divisions, and geographical distribution of the Laurentian deposits--Lower and Upper Laurentian--Reasons for believing that the Laurentian rocks are not azoic based upon their containing limestones, beds of oxide of iron, and graphite--The characters, chemical composition, and minute structure of _Eozoön Canadense_--Comparison of _Eozoön_ with existing Foraminifera--_Archoeosphoerinoe_--Huronian formation--Nature and distribution of Huronian deposits--Organic remains of the Huronian--Literature. CHAPTER VIII. The Cambrian period--General succession of Cambrian deposits in Wales--Lower Cambrian and Upper Cambrian--Cambrian deposits of the continent of Europe and North American--Life of the Cambrian period--Fucoids--Eophyton--Oldhamia--Sponges--Echinoderms--Annelides --Crustaceans--Structure of Trilobites--Brachiopods--Pteropods, Gasteropods, and Bivalves--Cephalopods--Literature. CHAPTER IX.