Preface  v.  vi.  vii.  viii.  ix.  x.

CHAPTER I. — On the different Classes of Rocks.

Geology defined — Successive formation of the earth's crust — Classification of rocks according to their origin and age — Aqueous rocks — Volcanic rocks — Plutonic rocks — Metamorphic rocks — The term primitive, why erroneously applied to the crystalline formations

CHAPTER II. — Aqueous Rocks — Their Composition and Formsof Stratification.

Mineral composition of strata — Arenaceous rocks — Argillaceous — Calcareous — Gypsum — Forms of stratification — Diagonal arrangement — Ripple-mark

CHAPTER III. — Arrangement of Fossils in Strata — Freshwater and Marine.

Limestones formed of corals and shells — Proofs of gradual increase of strata derived from fossils — Tripoli and semi-opal formed of infusoria — Chalk derived principally from organic bodies — Distinction of freshwater from marine formations — Alternation of marine and freshwater deposits

CHAPTER IV — Consolidation of Strata and Petrifaction of Fossils.

Chemical and mechanical deposits — Cementing together of particles — Concretionary nodules — Consolidating effects of pressure — Mineralization of organic remains — Impressions and casts how formed — Fossil wood — Source of lime and silex in solution

CHAPTER V. — Elevation of Strata above the Sea — Horizontal and Inclined
Stratification.

Position of marine strata, why referred to the rising up of the land, not to the going down of the sea — Upheaval of horizontal strata — Inclined and vertical stratification — Anticlinal and synclinal lines — Theory of folding by lateral movement — Creeps — Dip and strike — Structure of the Jura — Inverted position of disturbed strata — Unconformable stratification — Fractures of strata — Faults

CHAPTER VI. — Denudation.

Denudation defined — Its amount equal to the entire mass of stratified deposits in the earth's crust — Levelled surface of countries in which great faults occur — Denuding power of the ocean — Origin of Valleys — Obliteration of sea-cliffs — Inland sea-cliffs and terraces

CHAPTER VII. — Alluvium.

Alluvium described — Due to complicated causes — Of various ages — How distinguished from rocks in situ — River-terraces — ParalIel roads of Glen Roy 79

CHAPTER VIII. — Chronological Classification of Rocks.

Aqueous, plutonic, volcanic, and metamorphic rocks, cohsidered chronologically — Lehman's division into primitive and secondary — Werner's addition of a transition class — Neptunian theory — Hutton on igneous origin of granite — The name of "primary" for granite and the term "transition" why faulty — Chronological nomenclature adopted in this work, so far as regards primary,
secondary, and tertiary periods

[xii]
CHAPTER IX. — On the different Ages of the Aqueous Rocks.

On the three tests of relative age — superposition, mineral character, and fossils — Change of mineral character and fossils in the same formation — Proofs that distinct species of animals and plants have lived at successive periods — Distinct provinces of indigenous species — Similar laws prevailed at successive geological periods — Test of age by included fragments — Frequent absence of strata of intervening periods — General Table of Fossiliferous strata

CHAPTER X. — Classiflcation of Tertiary Fonnations — Post Pliocene Group.

General principles of classification of tertiary strata — Difficulties in determining their chronology — Increasing proportion of living species of shells in strata of newer origin — Terms Eocene, Miocene, and Pliocene — Post-Pliocene recent
strata - - - - - - - - - 109

CHAPTER XI. — Newer Pliocene Period. — Boulder Formation.

Drift of Scandinavia, northern Germany, and Russia — Fundamental rocks polished, grooved, and scratched — Action of glaciers and icebergs — Fossil shells of glacial period — Drift of eastern Norfolk — Ancient glaciers of North Wales — Irish drift

CHAPTER XII. — Boulder Formation — continued.

Effects of intense cold in augmenting the quantity of alluvium — Analogy of erratics and scored rocks in North America, Europe, and Canada — Why organic remains so rare in northern drift — Many shells and some quadrupeds survived the glacial cold — Alps an independent centre of dispersion of erratics — Meteorite in Asiatic drift

CHAPTER XIII. — Newer Pliocene Strata and Cavern Deposits.

Pleistocene formations — Freshwater deposits in valley of Thames — In Norfolk cliffs — In Patagonia — Comparative longevity of species in the mammalia and testacea — Crag of Norwich — Newer Pliocene strata of Sicily — Osseous breccias and cavern-deposits — Sicily — Kirkdale — Australian cave-breccias — Relationship of geographical provinces of living vertebrata and those of Pliocene species — Teeth of fossil quadrupeds

CHAPTER XIV. — Older Pliocenc and Miocene Formations.

Red and Coralline crags of Suffolk — Fossils, and proportion of recent species — Depth of sea, and climate — Migration of many species of shells southwards during the glacial period — Antwerp crag — Subapennine beds — Miocene formations — Faluns of Touraine — Depth of sea and littoral character of fauna — Climate — Proportion of recent species of shells — Miocene strata of Bordeaux, Belgium, and North Germany — Older Pliocene and Miocene formations in the United States — Sewalik Hills in India

CHAPTER XV. — Upper Eocene Formations. (Lower Miocene of many authors.)

Remarks on classification, and on the line of separation between Eocene and Miocene — Whether the Limburg strata in Belgium should be called Upper Eocene — Strata of same age in North Gerinany — Mayence basin — Brown Coal of Germany — Upper Eocene of Isle of Wight — Of France — Lacustrine strata of Auvergne and the Cantal — Upper Eocene of Bordeaux, &c. — Of Nebraska, United States

CHAPTER XVI. — Middle and Lower Eocene Formations.

Middle Eocene strata of England — Fluvio-marine series in the Isle of Wight and Hampshire — Successive groups of Eocene Mammalia — Fossils of Barton Clay — Of the Bagshot and Bracklesbarn beds — Lower Eocene strata of England — London Clay proper — Strata of Kyson in Suffolk — Fossil monkey and opossum — Plastic clays and sands — Thanet sands — Middle and Lower Eocene formations of France — Nummulitic formations of Europe and Asia — Eocene strata at Claiborne, Alabama — Colossal cetacean — Orbitoid limestone — Burrstone

Lapse of time between the Cretaceous and Eocene periods — Formations in Belgium and France of intermediate age — Pisolitic limestone — Divisions of the Cretaceous series in Northwestern Europe — Maestricht beds — Chalk of Faxoe — White chalk — How far derived from shells and corals — Chalk flints — Fossils of the Upper Cretaceous rocks — Upper Greensand and Gault — Chalk of South of Europe — Hippurite limestone — Cretaceous rocks of the United States

CHAPTER XVIII. — Lower Cretaceous and Wealden Formations.

Lower Greensand — Term "Neocomian" — Fossils of Lower Greensand — Wealden formation — Weald Clay and Hastings Sand — Fossil shells and fish — Their relation to the Cretaceous type — Flora of Lower Cretaceous and Wealden periods

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 — Denudation of the chalk and wealden in Surrey, Kent, and Sussex — Chalk once continuous from the North to the South Downs — Rise and denudation of the strata gradual — At what period the Weald valley was denuded, and by what causes — Elephant-bed, Brighton — Sangatte cliff — Conclusion

CHAPTER XX. — Jurassic Group. — Purbeck Beds and Oolite.

The Purbeck beds a member of the Upper Oolite — New fossil mammifer — Dirt-bed — Fossils of the Purbeck beds — Portland stone and fossils — Middle Oolite — Coral Rag — Zoophytes — Nerinæan limestone — Diceras limestone — Oxford Clay, Ammonites and Belemnites — Lower Oolite, Crinoideans — Great Oolite — Stonesfield Slate — Fossil mammalia — Yorkshire Oolitic coal-field — Brora coal — Fuller's Earth — Inferior Oolite and fossils

CHAPTER XXI. — Jurassic Group, continued. — Lias.

Mineral character of Lias — Fossil shells and fish — Radiata — Ichthyodorulites — Reptiles — Ichthyosaur and Plesiosaur — Fluvio-marine beds in Gloucestershire, and Insect limestone — Fossil plants — Origin of the Oolite and Lias — Oolitic coal-field of Virginia

CHAPTER XXII. — Trias or NewRed Sandstone Group.

Distinction between New and Old Red Sandstone — The Trias and its three divisions in Germany — Keuper and its fossils — Muschelkalk and fossils — Fossil plants of the Bunter — Triassic group in England — Footsteps of Cheirotherium — Osteology of the Labyrinthodon —Triassic mammifer — Origin of Red Sandstone and Rock-salt — New Red Sandstone in the United States — Fossil footprints of birds and reptiles in the valley of the Connecticut

CHAPTER XXIII. — Permian or Magnesian Limestone Group.

Fossils of Magnesian Limestone — Term Permian — English and German equivalents — Marine shells and corals — Palæoniscus and other fish — Thecodont sanrians — Permian Flora — Its generic affinity to the carboniferous — Psaronites or tree-ferns

CHAPTER XXIV. — The Coal, or Carboniferous Group.

Carboniferous strata in England — Coal-measures and mountain limestone — Carboniferous series in Ireland and South Wales — Underclays with Stigmaria — Carboniferous Flora — Ferns, Lepidodendra, Calamites, Sigillariæ — Coniferæ — Sternbergia — Trigonocarpon — Grade of Coniferæ in the Vegetable Kingdom — Absence of Angiosperms — Coal, how formed — Erect fossil trees — Rain-prints — Purity of the Coal explained — Time required for its accumulation — Crustaceans and insects

[xiv]

CHAPTER XXV. Carboniferous Group— continued.

Coal-fields of the United States — Section of the country between the Atlantic and Mississippi — Uniting of many coal-seams into one thick bed — Vast extent and continuity of single seams of coal — Ancient river-channel in Forest of Dean coal-field — Climate of Carboniferous period — Insects in coal — Great number of fossil fish — First discovery of the skeletons of fossil reptiles — First land-shell of the coal found — Rarity of air-breathers, whether vertebrate or invertebrate, in Coal-measures — Mountain limestone — Its corals and marine shells

CHAPTER XXVI — Old Red Sandstone or Devonian Group.

Old Red Sandstone of the borders of Wales — Scotland and the South of Ireland — Fossil reptile of Elgin — Fossil Devonian plants at Kilkenny — Ichthyolites of Clashbinnie — Fossil fish, &c., crustaceans of Caithness and Forfarshire — Distinet lithological type of Old Red in Devon and Cornwall — Term "Devonian" — Devonian series of England and the Continent — Old Red Sandstone of Russia Devonian strata of the United States

CHAPTER XXVII. — Silurian and Cambrian Groups.

Silurian strata formerly called "Transition" — Subdivisions — Lndlow formation and fossils — Ludlow bone-bed, and oldest known remains of fossil fish — Wenlock formation, corals, cystideans, trilobites — Caradoc sandstone — Pentameri and Tentaculites — Lower Silurian rocks — Llandeilo flags — Cystideæ — Trilobites — Graptolites — Vast thickness of Lower Silurian strata in Wales — Foreign Silurian equivalents in Europe — Ungulite grit of Russia — Silurian strata of the United States — Canadian equivalents — Deep-sea origin of Silurian strata — Fossiliferous rocks below the Llandeilo beds — Cambrian group — Lingula flags — Lower Cambrian — Oldest known fossil remains — "Primordial group" of Bohemia — Metamorphosis of trilobites — Alum schists of Sweden and Norway — Potsdam sandstone of United States and Canada — Trilobites on the Upper Mississippi — Supposed period of invertebrate animals — Absence of fish in Lower Silurian — Progressive discovery of vertebrata in older rocks — Doctrine of the non-existence of vertebrata in the older fossiliferous periods premature

CHAPTER XXVIII — Volcanic Rocks.

Trap rocks — Name, whence derived — Their igneous origin at first doubted — Their general appearance and character — Mineral composition and texture — Varieties of felspar — Hornblende and augite — Isomorphism — Rocks, how to be studied — Basalt, trachyte, greenstone, porphyry, scoria, amygdaloid, lava, tuft — Agglomerate — Laterite — Alphabetical list, and explanation of names and synonyms of volcanic rocks — Table of analyses of minerals most abundant in the volcanic and hypogene rocks

CHAPTER XXIX. — Volcanic Rocks — continued.

Trap dikes — Strata altered at or near the contact — Conversion of chalk into marble — Trap interposed between strata — Columnar and globular structure — Relation of trappean rocks to the products of active volcanoes — Form, external structure, and origin of volcanic mountains — Craters and Calderas — Sandwich Islands — Lava flowing underground — Truncation of cones — Javanese Calderas — Canary Islands — Structure and origin of the caldera of Palma — Aqueous conglomerate in Palma — Hypothesis of upheaval considered — Slope on which stony lavas may form — Island of St. Paul in the Indian Ocean — Peak of Teneriffe, and ruins of older cone — Madeira — Its volcanic rocks, partly of marine and partly of subaerial origin — Central axis of eruptions — Varying dip of solid lavas near the axis, and further from it — Leaf-bed and fossil land-plants — Central valleys of Madeira how formed

[xv]
CHAPTER XXX. — On the Different Ages of the Volcanic Rocks.

Tests of relative age of volcanic rocks — Tcst by superposition and intrusion — Test by alteration of rocks in contact — Test by organic remains — Test of age by mineral character — Test by included fragments — Volcanic rocks of the Post Pliocene period — Basalt of Bay of Trezza in Sicily — Post-Pliocene volcanic rocks near Naples — Dikes of Somma — Igneous formations of the Newer Pliocene period — Val di Noto in Sicily

CHAPTER XXXI — On theDifferent Ages of the Volcanic Rocks — continued.

Volcanic rocks of the Older Pliocene period — Tuscany — Rome — Volcanic region of Olot in Catalonia — Cones and lava-currents — Miocene period — Brown-coal of the Eifel and contemporaneous trachytic rocks — Age of the brown-coal — Peculiar characters of the volcanoes of the Upper and Lowcr Eifel — Lake craters — Trass — Hungarian volcanoes

CHAPTER XXXII — On the Different Ages of the Volcanic Rocks — continued.

Volcanic rocks of the Pliocene and Miocene periods continued — Auvergne — Mont Dor — Breccias and alluviums of Mont Perrier, with bones of quadrupeds — Mont Dome — Cones not denuded by general flood — Velay — Bones of quadrupeds buried in scoriæ — Cantal — Eocene volcanic rocks — Tuffs near Clermont — Hill of Gergovia — Trap of Cretaceous period — Oolitic period — New Red Sandstone period — Carboniferous period — Old Red Sandstone period — Silurian period — Cambrian volcanic rocks

CHAPTER XXXIII — Plutonic Rocks — Granite.

General aspect of granite — Analogy and difference of volcanic and plutonic formations — Minerals in granite — Mutual penetration of crystals of quartz and felspar — Syenitic, talcose, and schorly granites — Eurite — Passage of granite into trap — Granite veins in Glen Tilt, and other countries — Composition of granite veins — Metalliferous veins in strata near their junction with granite — Quartz veins — Whether plutonic rocks are ever overlying — Their exposuie at the surface due to denudation

CHAPTER XXXIV. — On the different Ages of the Plutonic Rocks.

Difficulty in ascertaining the age of a plutonic rock — Test of age by relative position — Test by intrusion and alteration — Test by mineral composition — Test by included fragments — Recent and Pliocene plutonic rocks, why invisible — Tertiary plutonic rocks in the Andes — Granite altering Cretaceous rocks — Granite altering Lias — Granite altering Carboniferous strata — Granite of the Old Red Sandstone period — Syenite altering Silurian strata in Norway — Oldest plutonic rocks — Granite protruded in a solid form — Age of the granites of Arran, in Scotland

CHAPTER XXXV — Metamorphic Rocks.

General character of metamorphic rocks — Gneiss — Hornblende-schist — Mica schist — Clay-slate — Quartzite — Chlorite-schist — Metamorphic limestone — Alphabetical list and explanation of the more abundant rocks of this family — Origin of the metamorphic strata — Their stratification — Fossiliferous strata near intrusive masses of granite converted into different members of the metamorphic series — Objections to the metamorphic theory considered — Partial conversion of Eocene slate into gneiss

CHAPTER XXXVI — Metamorphic Rocks. — continued.

Origin of the metamorphic rocks, continued — Definition of joints, slaty cleavage, and foliation — Causes of these structures — Mechanical theory of cleavage — Supposed combination of crystalline and mechanical forces — Lamination of some volcanic rocks due to motion — Whether the foliation of the crystalline schists be usually parallel with the original planes of stratification

[xvi]
CHAPTER XXXVII — On the different Ages of the Metamorphic Rocks.

Age of each set of metamorphic strata twofold — Test of age by fossils and mineral character not available — Test by superposition ambiguous — Conversion of fossiliferous strata into metamorphic rocks — Limestone and shale of Carrara — Metamorphic strata older than the Cambrian rocks — Others of Lower Silurian origin — Others of the Jurassic and Eocene periods — Why scarcely any of the visible crystalline strata are very modern — Order of succession in metamorphic socks — Uniformity of mineral character — Why the metamorphic strata are less calcareous than the fossiliferous

CHAPTER XXXVIII. — Mineral Veins.

Werner's doctrine, that mineral veins were fissures filled from above — Veins of segregation — Ordinary metalliferous veins or lodes — Their frequent coincidence with faults — Proofs that they originated in fissures in solid rock — Veins shifting other veins — Polishing of their walls or "slicken-sides" — Shells and pebbles in lodes — Evidence of the successive enlargement and reopening of veins — Why some veins alternately swell out and contract — Filling of lodes by sublimation from below — Chemical and electrical action — Relative age of the precious metals — Copper and lead veins in Ireland older than Cornish tin — Lead veins in Lias, Glamorganshire — Gold in Russia, California, and Australia — Connection of hot springs and mineral veins — Concluding remarks  618  619  620  621  622  623  624  625  626  627  628  629  630  631  632

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British Pliocene Strata — Proofs from fossil shells of a gradual refrigeration of climate in England at the successive periods of the Coralline, the Red, and the Norwich Crag — Searles Wood's Monograph on the Crag Mollusca — The Crag Mastodon, a Pliocene species — Different assemblages of fossil Mammalia in the freshwater and drift deposits of the valley of the Thames — Fossil Musk-buffalo in the drift near London and near Berlin

Where to draw the line between the Miocene and Focene Tertiary Strata.

Classification of the Miocene and Eocene strata — Where to draw the line between Upper Eocene and Lower Miocene — Reasons for a proposed change of nomenclature — Miocene fossil shells and quadrupeds of the Sewâlik or Sub-Himalayan Hills

Miocene Fauna of theSewâlikHills  645

Denudation of the Wealden

Discovery of the Lower Crag on the summit of the North Downs between Folkestone and Dorking

New Fossil Mammalia from the Purbeck orUpper Oolitic Strata in Dorsetshire.

Discovery in Dorsetshire of seven or eight new genera of Mammalia in the Purbeck or Upper Oolite strata — First example of a skull of a Mammifer from Secondary Rocks — Insectivorous Marsupials and Placentals and herbivorous Marsupials — Figures and descriptions — Light thrown on the Microlestes or oldest triassic Mammifer — General bearing of the new facts

Discovery of Mammalian, Remains in Rocks of highAntiquity in North Carolina,United States  658  659  660

Upper Trias of the Eastern Alps.

Recognition of a Marine equivalent of the Upper Trias in the Austrian Alps — True position of the St. Cassian and Hallstatt Beds — 800 new species of triassic Mollusca and Radiata — Links thus supplied for connecting the Paleozoic and Neozoic faunas

On the supposed evidence of Phœnogamous Plants (not Gymnosperms) in the Coal Formation  663  664

Silurian and Cambrian Rocks and M. Barrande's theory of Colonies -  664  665  666  667  668  669

Antiquity of Fossil Birds  669

Index  671  672  673  674  675  676  677  678  679  680  681  682  683  684  685