The Lower Silurian period--The Silurian rocks generally--Limits of Lower and Upper Silurian--General succession, subdivisions, and characters of the Lower Silurian rocks of Wales--General succession, subdivisions, and characters of the Lower Silurian rocks of the North American continent--Life of the period--Fucoids--Protozoa--Graptolites--Structure of Graptolites--Corals--General structure of Corals--Crinoids-- Cystideans--General characters of Cystideans--Annelides-- Crustaceans--Polyzoa--Brachiopods--Bivalve and Univalve Molluscs--Chambered Cephalopods--General characters of the Cephalopoda--Conodonts. CHAPTER X. The Upper Silurian period--General succession of the Upper Silurian deposits of Wales--Upper Silurian deposits of North America--Life of the Upper Silurian--Plants--Protozoa--Graptolites--Corals-- Crinoids--General structure of Crinoids--Star-fishes--Annelides-- Crustaceans--Eurypterids--Polyzoa--Brachiopods--Structure of Brachiopods--Bivalves and Univalves--Pteropods--Cephalopods-- Fishes--Silurian literature. CHAPTER XI. The Devonian period--Relations between the Old Red Sandstone and the marine Devonian deposits--The Old Red Sandstone of Scotland--The Devonian strata of Devonshire--Sequence and subdivisions of the Devonian deposits of North America--Life of the period--Plants--Protozoa--Corals-Crinoids--Pentremites-- Annelides--Crustaceans--Insects--Polyzoa--Brachiopods--Bivalves-- Univalves--Pteropods--Cephalopods--Fishes--General divisions of the Fishes--Palæontological evidence as to the independent existence of the Devonian system as a distinct formation--Literature. CHAPTER XII. The Carboniferous period--Relations of Carboniferous rocks to Devonian--The Carboniferous Limestone or Sub-Carboniferous series--The Millstone-grit and the Coal-measures--Life of the period--Structure and mode of formation of Coal--Plants of the Coal. CHAPTER XIII. Animal life of the Carboniferous period--Protozoa--Corals-- Crinoids--Pentremites--Structure of Pentremites--Echinoids-- Structure of Echinoidea--Annelides--Crustacea--Insects-- Arachnids--Myriapods--Polyzoa--Brachiopods--Bivalves and Univalves--Cephalopods--Fishes--Labyrinthodont Amphibians-- Literature. CHAPTER XIV. The Permian period--General succession, characters, and mode of formation of the Permian deposits--Life of the period-- Plants--Protozoa--Corals--Echinoderms--Annelides--Crustaceans-- Polyzoa--Brachiopods--Bivalves-Univalves--Pteropods-- Cephalopods--Fishes--Amphibians--Reptiles--Literature. CHAPTER XV. The Triassic period--General characters and subdivisions of the Trias of the Continent of Europe and Britain--Trias of North America--Life of the period--Plants--Echinoderms--Crustaceans-- Polyzoa--Brachiopods--Bivalves--Univalves--Cephalopods-- Intermixture of Palæozoic with Mesozoic types of Molluscs-- Fishes--Amphibians--Reptiles--Supposed footprints of Birds-- Mammals--Literature. CHAPTER XVI.