CONTENTS. ix 



CHAPTER XV. 



CRETACEOUS GROUP. 



White chalk Its marine origin shown by fossil shells Extinct genera of 

 cephalopoda Sponges and corals in the chalk No terrestrial or fluviatile 

 shells, no land plants Supposed origin of white chalk from decomposed 

 corals (p. 186.) Single pebbles, whence derived Cretaceous coral-reef in 

 Denmark (p. 188.) Maestricht beds and fossils Origin of flint in chalk 

 Wide area covered by chalk (p. 191.) Green-sand formation and fossils 

 Origin of External configuration of chalk (p. 193.) Outstanding columns 

 or needles Period of emergence from the sea Difference of the chalk of 

 the north and south of Europe Hippurites Nummulites (p. 198.) 

 Altered lithological character of cretaceous formation in Spain and Greece 

 Terminology. 



CHAPTER XVI. 



WEALDEN GROUP. 



The Wealden, including the Weald clay, Hastings sand, and Purbeck beds 

 Intercalated between two marine formations Fossil shells freshwater, with 

 a few marine Cypris Fish Reptiles (p. 202.) Birds Plants Section 

 showing passage of Wealden beneath chalk Junction of Wealden and 

 Oolite Dirt-bed (p. 205.) Theory of gradual subsidence Proofs that the 

 Wealden strata, notwithstanding their thickness, may have been formed in 

 shallow water (p. 208.) Geographical extent of Wealden Bray near 

 Beauvais Relation of the Wealden to the Lower Green-sand and Oolite 

 (p. 211.) 



CHAPTER XVII. 



OOLITE AND LIAS. 



Subdivisions of the Oolitic group Fossil shells Corals in the calcareous 



divisions only Buried forest of Encrinites in Bradford clay (p. 216.) 



Changes in organic life during accumulation of Oolites Characteristic 

 fossils Signs of neighbouring land and shoals (p. 221.) Supposed cetacea 

 in Oolite Oolite of Yorkshire and Scotland (p. 223.) 



CHAPTER XVIII. 



OOLITE AND LIAS continued. 



Mineral character of Lias Name of Gryphite limestone Fossil fish 



Ichthyodorulites Reptiles of the Lias (p. 227.) Ichthyosaur and Plesiosaur 



Newly-discovered marine Reptile of the Galapagos Islands (p. 229.) 



Sudden death and burial of fossil animals in Lias Origin of the Oolite and 

 Lias, and of altejnating calcareous and argillaceous formations (p. 232.) 

 Physical geography (p. 234.) Vales of clay Hills and escarpments of 

 limestone. 



