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 XVn. 



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 XVm. 



OOLITE AND LIAS — Continued. 



Mineral character of Lias — Name of Gryphite limestone — Fossil fish — 

 IchthyodoruUtes — • 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 OoKte and 

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

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

 limestone. 



