CONTENTS. xi 



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 Conodoiits, . . 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 literature, . . 115-132 



CHAPTER XI. 



The Devorfian 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 Palseontological evidence as to the inde- 

 pendent existence of the Devonian system as a distinct formation 

 Literature, 132-157 



CHAPTER XII. 



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 Structure and mode of formation of Coal Plants of the 

 Coal, . 157-170 



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 Litera- 

 ture, 170-192 



