CONTENTS. xi 



CHAPTER VIII. 



The Cambrian period General succession of Cambrian de- 

 posits in Wales Lower Cambrian and Upper Cambrian 

 Cambrian deposits of the continent of Europe and 

 North America Life of the Cambrian period Fucoids 

 Eophyton Oldhamia Sponges Echinoderms An - 

 nelides Crustaceans Structure of Trilobites Brachio- 

 pods, Gasteropods, and Bivalves Cephalopoda Litera- 

 ture 77-Qi 



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 succession, subdivisions and charac- 

 ters 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 

 character of Cystideans Annelides Crustaceans Poly- 

 zoa Brachiopods Bivalve and Univalve Molluscs 

 Chambered Cephalopods General characters of the 

 Cephalopoda Conodonts 91-1 16 



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 struc- 

 ture of Crinoids Star-fishes Annelides Crustaceans 

 Eurypterids Polyzoa Brachiopods Structure of Bra- 

 chiopods Bivalves and Univalves Pteropods Cephal- 

 opods Fishes Silurian literature 1 16-134 



CHAPTER XI. 



The Devonian period Relation between the Old Red Sand- 

 stone and the marine Devonian deposits The Old Red 

 Sandstone of Scotland The Devonian strata of Devon- 

 shire Sequence and subdivisions of the Devonian de- 

 posits 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 Palaeontological evidence as to 

 the independent existence of the Devonian system as a 

 distinct formation Literature 134-160 



