Part 4 (1/2)

CHAPTER XV.

UPPER EOCENE FORMATIONS.

Eocene areas in England and France--Tabular view of French Eocene strata--Upper Eocene group of the Paris basin--Same beds in Belgium and at Berlin--Mayence tertiary strata--Freshwater upper Eocene of Central France--Series of geographical changes since the land emerged in Auvergne--Mineral character an uncertain test of age--Marls containing Cypris--Oolite of Eocene period--Indusial limestone and its origin--Fossil mammalia of the upper Eocene strata in Auvergne--Freshwater strata of the Cantal, calcareous and siliceous--Its resemblance to chalk--Proofs of gradual deposition of strata 174

CHAPTER XVI.

EOCENE FORMATIONS--_continued_.

Subdivisions of the Eocene group in the Paris basin--Gypseous series--Extinct quadrupeds--Impulse given to geology by Cuvier's osteological discoveries--Sh.e.l.ly sands called sables moyens--Calcaire grossier--Miliolites--Calcaire siliceux--Lower Eocene in France--Lits coquilliers--Sands and plastic clay--English Eocene strata--Freshwater and fluvio-marine beds--Barton beds--Bagshot and Bracklesham division--Large ophidians and saurians--Lower Eocene and London Clay proper--Fossil plants and sh.e.l.ls--Strata of Kyson in Suffolk--Fossil monkey and opossum--Mottled clays and sand below London Clay--Nummulitic formation of Alps and Pyrenees--Its wide geographical extent--Eocene strata in the United States--Section at Claiborne, Alabama--Colossal cetacean--Orbitoid limestone--Burr stone 190

CHAPTER XVII.

CRETACEOUS GROUP.

Divisions of the cretaceous series in North-Western Europe--Upper cretaceous strata--Maestricht beds--Chalk of Faxoe--White chalk--Characteristic fossils--Extinct cephalopoda--Sponges and corals of the chalk--Signs of open and deep sea--White area of white chalk--Its origin from corals and sh.e.l.ls--Single pebbles in chalk--Siliceous sandstone in Germany contemporaneous with white chalk--Upper greensand and gault--Lower cretaceous strata--Atherfield section, Isle of Wight--Chalk of South of Europe--Hippurite limestone--Cretaceous Flora--Chalk of United States 209

CHAPTER XVIII.

WEALDEN GROUP.

The Wealden divisible into Weald Clay, Hastings Sand, and Purbeck Beds--Intercalated between two marine formations--Weald clay and Cypris-bearing strata--Iguanodon--Hastings sands--Fossil fish--Strata formed in shallow water--Brackish water-beds--Upper, middle, and lower Purbeck--Alternations of brackish water, freshwater, and land--Dirt-bed, or ancient soil--Distinct species of fossils in each subdivision of the Wealden--Lapse of time implied--Plants and insects of Wealden--Geographical extent of Wealden--Its relation to the cretaceous and oolitic periods--Movements in the earth's crust to which it owed its origin and submergence 225

CHAPTER XIX.

DENUDATION OF THE CHALK AND WEALDEN.

Physical geography of certain districts composed of Cretaceous and Wealden strata--Lines of inland chalk-cliffs on the Seine in Normandy--Outstanding pillars and needles of chalk--Denudation of the chalk and Wealden in Surrey, Kent, and Suss.e.x--Chalk once continuous from the North to the South Downs--Anticlinal axis and parallel ridges--Longitudinal and transverse valleys--Chalk escarpments--Rise and denudation of the strata gradual--Ridges formed by harder, valleys by softer beds--Why no alluvium, or wreck of the chalk, in the central district of the Weald--At what periods the Weald valley was denuded--Land has most prevailed where denudation has been greatest--Elephant bed, Brighton 238

CHAPTER XX.

OOLITE AND LIAS.

Subdivisions of the Oolitic or Jura.s.sic group--Physical geography of the Oolite in England and France--Upper Oolite--Portland stone and fossils--Lithographic stone of Solenhofen--Middle Oolite, coral rag--Zoophytes--Nerinaean limestone--Diceras limestone--Oxford clay, Ammonites and Belemnites--Lower Oolite, Crinoideans--Great Oolite and Bradford clay--Stonesfield slate--Fossil mammalia, placental and marsupial--Resemblance to an Australian fauna--Doctrine of progressive development--Collyweston slates--Yorks.h.i.+re Oolitic coal-field--Brora coal--Inferior Oolite and fossils 257

CHAPTER XXI.

OOLITE AND LIAS--_continued_.

Mineral character of Lias--Name of Gryphite limestone--Fossil sh.e.l.ls and fish--Ichthyodorulites--Reptiles of the Lias--Ichthyosaur and Plesiosaur--Marine Reptile of the Galapagos Islands--Sudden destruction and burial of fossil animals in Lias--Fluvio-marine beds in Gloucesters.h.i.+re and insect limestone--Origin of the Oolite and Lias, and of alternating calcareous and argillaceous formations--Oolitic coal-field of Virginia, in the United States 273

CHAPTER XXII.