[Chapter XXI—TRIAS, OR NEW RED SANDSTONE GROUP.]
Beds of Passage between the Lias and Trias, Rhætic Beds. — Triassic Mammifer. — Triple Division of the Trias. — Keuper, or Upper Trias of England. — Reptiles of the Upper Trias. — Foot-prints in the Bunter formation in England. — Dolomitic Conglomerate of Bristol. — Origin of Red Sandstone and Rock-salt. — Precipitation of Salt from inland Lakes and Lagoons. — Trias of Germany. — Keuper. — St. Cassian and Hallstadt Beds. — Peculiarity of their Fauna. — Muschelkalk and its Fossils. — Trias of the United States. — Fossil Foot-prints of Birds and Reptiles in the Valley of the Connecticut. — Triassic Mammifer of North Carolina. — Triassic Coal-field of Richmond, Virginia. — Low Grade of early Mammals favourable to the Theory of Progressive Development.
[Chapter XXII—PERMIAN OR MAGNESIAN LIMESTONE GROUP.]
Line of Separation between Mesozoic and Palæozoic Rocks. — Distinctness of Triassic and Permian Fossils. — Term Permian. — Thickness of calcareous and sedimentary Rocks in North of England. — Upper, Middle, and Lower Permian. — Marine Shells and Corals of the English Magnesian Limestone. — Reptiles and Fish of Permian Marl-slate. — Foot-prints of Reptiles. — Angular Breccias in Lower Permian. — Permian Rocks of the Continent. — Zechstein and Rothliegendes of Thuringia. — Permian Flora. — Its generic Affinity to the Carboniferous.
[Chapter XXIII—THE COAL OR CARBONIFEROUS GROUP.]
Principal Subdivisions of the Carboniferous Group. — Different Thickness of the sedimentary and calcareous Members in Scotland and the South of England. — Coal-measures. — Terrestrial Nature of the Growth of Coal. — Erect fossil Trees. — Uniting of many Coal-seams into one thick Bed. — Purity of the Coal explained. — Conversion of Coal into Anthracite. — Origin of Clay-ironstone. — Marine and brackish-water Strata in Coal. — Fossil Insects. — Batrachian Reptiles. — Labyrinthodont Foot-prints in Coal-measures. — Nova Scotia Coal-measures with successive Growths of erect fossil Trees. — Similarity of American and European Coal. — Air-breathers of the American Coal. — Changes of Condition of Land and Sea indicated by the Carboniferous Strata of Nova Scotia.
[Chapter XXIV—FLORA AND FAUNA OF THE CARBONIFEROUS PERIOD.]
Vegetation of the Coal Period. — Ferns, Lycopodiaceæ, Equisetaceæ, Sigillariæ, Stigmariæ, Coniferæ. — Angiosperms. — Climate of the Coal Period. — Mountain Limestone. — Marine Fauna of the Carboniferous Period. — Corals. — Bryozoa, Crinoidea. — Mollusca. — Great Number of fossil Fish. — Foraminifera.
[Chapter XXV—DEVONIAN OR OLD RED SANDSTONE GROUP.]
Classification of the Old Red Sandstone in Scotland and in Devonshire. — Upper Old Red Sandstone in Scotland, with Fish and Plants. — Middle Old Red Sandstone. — Classification of the Ichthyolites of the Old Red, and their Relation to Living Types. — Lower Old Red Sandstone, with Cephalaspis and Pterygotus. — Marine or Devonian Type of Old Red Sandstone. — Table of Devonian Series. — Upper Devonian Rocks and Fossils. — Middle. — Lower. — Eifel Limestone of Germany. — Devonian of Russia. — Devonian Strata of the United States and Canada. — Devonian Plants and Insects of Canada.
[Chapter XXVI—SILURIAN GROUP.]
Classification of the Silurian Rocks. — Ludlow Formation and Fossils. — Bone-bed of the Upper Ludlow. — Lower Ludlow Shales with Pentamerus. — Oldest known Remains of fossil Fish. — Table of the progressive Discovery of Vertebrata in older Rocks. — Wenlock Formation, Corals, Cystideans and Trilobites. — Llandovery Group or Beds of Passage. — Lower Silurian Rocks. — Caradoc and Bala Beds. — Brachiopoda. — Trilobites. — Cystideæ. — Graptolites. — Llandeilo Flags. — Arenig or Stiper-stones Group. — Foreign Silurian Equivalents in Europe. — Silurian Strata of the United States. — Canadian Equivalents. — Amount of specific Agreement of Fossils with those of Europe.
[Chapter XXVII—CAMBRIAN AND LAURENTIAN GROUPS.]
Classification of the Cambrian Group, and its Equivalent in Bohemia. — Upper Cambrian Rocks. — Tremadoc Slates and their Fossils. — Lingula Flags. — Lower Cambrian Rocks. — Menevian Beds. — Longmynd Group. — Harlech Grits with large Trilobites. — Llanberis Slates. — Cambrian Rocks of Bohemia. — Primordial Zone of Barrande. — Metamorphosis of Trilobites. — Cambrian Rocks of Sweden and Norway. — Cambrian Rocks of the United States and Canada. — Potsdam Sandstone. — Huronian Series. — Laurentian Group, upper and lower. — Eozoon Canadense, oldest known Fossil. — Fundamental Gneiss of Scotland.
[Chapter XXVIII—VOLCANIC ROCKS.]
External Form, Structure, and Origin of Volcanic Mountains. — Cones and Craters. — Hypothesis of “Elevation Craters” considered. — Trap Rocks. — Name whence derived. — Minerals most abundant in Volcanic Rocks. — Table of the Analysis of Minerals in the Volcanic and Hypogene Rocks. — Similar Minerals in Meteorites. — Theory of Isomorphism. — Basaltic Rocks. — Trachytic Rocks. — Special Forms of Structure. — The columnar and globular Forms. — Trap Dikes and Veins. — Alteration of Rocks by volcanic Dikes. — Conversion of Chalk into Marble. — Intrusion of Trap between Strata. — Relation of trappean Rocks to the Products of active Volcanoes.
[Chapter XXIX—ON THE AGES OF VOLCANIC ROCKS.]
Tests of relative Age of Volcanic Rocks. — Why ancient and modern Rocks cannot be identical. — Tests by Superposition and intrusion. — Test by Alteration of Rocks in Contact. — Test by Organic Remains. — Test of Age by Mineral Character. — Test by Included Fragments. — Recent and Post-pliocene volcanic Rocks. — Vesuvius, Auvergne, Puy de Come, and Puy de Pariou. — Newer Pliocene volcanic Rocks. — Cyclopean Isles, Etna, Dikes of Palagonia, Madeira. — Older Pliocene volcanic Rocks. — Italy. — Pliocene Volcanoes of the Eifel. — Trass.
[Chapter XXX—AGE OF VOLCANIC ROCKS—CONTINUED.]
Volcanic Rocks of the Upper Miocene Period. — Madeira. — Grand Canary. — Azores. — Lower Miocene Volcanic Rocks. — Isle of Mull. — Staffa and Antrim. — The Eifel. — Upper and Lower Miocene Volcanic Rocks of Auvergne. — Hill of Gergovia. — Eocene Volcanic Rocks of Monte Bolca. — Trap of Cretaceous Period. — Oolitic Period. — Triassic Period. — Permian Period. — Carboniferous Period. — Erect Trees buried in Volcanic Ash in the Island of Arran. — Old Red Sandstone Period. — Silurian Period. — Cambrian Period. — Laurentian Volcanic Rocks.