CONTENTS. Xl 



CHAPTER IX. 



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 succes- 

 sion, subdivisions, and characters of the Lower Silurian rocks 

 of the North American continent — Life of the period — Fucoids — 

 Protozoa — Graptolites — Structure of Graptolites — Corals — Gene- 

 ral 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, . . 90-114 



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 hterature, . . 1 15-132 



CHAPTER XL 



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 — Bi- 

 valves — Univalves — Pteropods — Cephalopods — Fishes — General 

 divisions of the Fishes — Palaeontological evidence as to the inde- 

 pendent existence of the Devonian system as a distinct formation 

 — Literature, 132-157 



CHAPTER XIL 



The Carboniferous period — Relations of Carboniferous rocks to De- 

 vonian — The Carboniferous Limestone or Sub - Carboniferous 

 series — The Millstone-grit and the Coal-measures— Life of the 

 period — Stnicture and mode of formation of Coal — Plants of the 

 Coal, 157-170 



CHAPTER XHL 



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 — Litera- 

 ture, . . . . . . . . . . 170-192 



