The Student's Elements of Geology 1

The Student's Elements of Geology 1

The Student's Elements of Geology

: Sir Charles Lyell

 

PREFACE.

 

The LAST or sixth EDITION of my "Elements of Geology" was already out of print

before the end of 1868, in which year I brought out the tenth edition of my

"Principles of Geology."

 

In writing the last-mentioned work I had been called upon to pass in review

almost all the leading points of speculation and controversy to which the rapid

advance of the science had given rise, and when I proposed to bring out a new

edition of the "Elements" I was strongly urged by my friends not to repeat these

theoretical discussions, but to confine myself in the new treatise to those

parts of the "Elements" which were most indispensable to a beginner. This was to

revert, to a certain extent, to the original plan of the first edition; but I

found, after omitting a great number of subjects, that the necessity of bringing

up to the day those which remained, and adverting, however briefly, to new

discoveries, made it most difficult to confine the proposed abridgment within

moderate limits. Some chapters had to be entirely recast, some additional

illustrations to be introduced, and figures of some organic remains to be

replaced by new ones from specimens more perfect than those which had been at my

command on former occasions. By these changes the work assumed a form so

different from the sixth edition of the "Elements," that I resolved to give it a

new title and call it the "Student's Elements of Geology."

 

In executing this task I have found it very difficult to meet the requirements

of those who are entirely ignorant of the science. It is only the adept who has

already overcome the first steps as an observer, and is familiar with many of

the technical terms, who can profit by a brief and concise manual. Beginners

wish for a short and cheap book in which they may find a full explanation of the

leading facts and principles of Geology. Their wants, I fear, somewhat resemble

those of the old woman in New England, who asked a bookseller to supply her with

"the cheapest Bible in the largest possible print."

 

But notwithstanding the difficulty of reconciling brevity with the copiousness

of illustration demanded by those who have not yet mastered the rudiments of the

science, I have endeavoured to abridge the work in the manner above hinted at,

so as to place it within the reach of many to whom it was before inaccessible.

 

CHARLES LYELL.

 

73 Harley Street, London,

December, 1870.

 

 

CONTENTS.

 

 

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.

Their Stratification and imbedded Fossils.

Volcanic Rocks, with and without Cones and Craters.

Plutonic Rocks, and their Relation to the Volcanic.

Metamorphic Rocks, and their probable Origin.

The term Primitive, why erroneously applied to the Crystalline Formations.

Leading Division of the Work.

 

 

CHAPTER II.

 

AQUEOUS ROCKS-- THEIR COMPOSITION AND FORMS OF STRATIFICATION.

 

Mineral Composition of Strata.

Siliceous Rocks.

Argillaceous.

Calcareous.

Gypsum.

Forms of Stratification.

Original Horizontality.

Thinning out.

Diagonal Arrangement.

Ripple-mark.

 

 

CHAPTER III.

 

ARRANGEMENT OF FOSSILS IN STRATA-- FRESH-WATER AND MARINE.

 

Successive Deposition indicated by Fossils.

Limestones formed of Corals and Shells.

Proofs of gradual Increase of Strata derived from Fossils.

Serpula attached to Spatangus.

Wood bored by Teredina.

Tripoli formed of Infusoria.

Chalk derived principally from Organic Bodies.

Distinction of Fresh-water from Marine Formations.

Genera of Fresh-water and Land Shells.

Rules for recognising Marine Testacea.

Gyrogonite and Chara.

Fresh-water Fishes.

Alternation of Marine and Fresh-water Deposits.

Lym-Fiord.

 

 

CHAPTER IV.

 

CONSOLIDATION OF STRATA AND PETRIFACTION OF FOSSILS.

 

Chemical and Mechanical Deposits.

Cementing together of Particles.

Hardening by Exposure to Air.

Concretionary Nodules.

Consolidating Effects of Pressure.

Mineralization of Organic Remains.

Impressions and Casts: how formed.

Fossil Wood.

Goppert's Experiments.

Precipitation of Stony Matter most rapid where Putrefaction is going on.

Sources of Lime and Silex in Solution.

 

 

CHAPTER V.

 

ELEVATION OF STRATA ABOVE THE SEA.-- HORIZONTAL AND INCLINED STRATIFICATION.

 

Why the Position of Marine Strata, above the Level of the Sea, should be

referred to the rising up of the Land, not to the going down of the Sea.

Strata of Deep-sea and Shallow-water Origin alternate.

Also Marine and Fresh-water Beds and old Land Surfaces.

Vertical, inclined, and folded Strata.

Anticlinal and Synclinal Curves.

Theories to explain Lateral Movements.

Creeps in Coal-mines.

Dip and Strike.

Structure of the Jura.

Various Forms of Outcrop.

Synclinal Strata forming Ridges.

Connection of Fracture and Flexure of Rocks.

Inverted Strata.

Faults described.

Superficial Signs of the same obliterated by Denudation.

Great Faults the Result of repeated Movements.

Arrangement and Direction of parallel Folds of Strata.

Unconformability.

Overlapping Strata.

 

 

CHAPTER VI.

 

DENUDATION.

 

Denudation defined.

Its Amount more than equal to the entire Mass of Stratified Deposits in the

Earth's Crust.

Subaerial Denudation.

Action of the Wind.

Action of Running Water.

Alluvium defined.

Different Ages of Alluvium.

Denuding Power of Rivers affected by Rise or Fall of Land.

Littoral Denudation.

Inland Sea-Cliffs.

Escarpments.

Submarine Denudation.

Dogger-bank.

Newfoundland Bank.

Denuding Power of the Ocean during Emergence of Land.

 

 

CHAPTER VII.

 

JOINT ACTION OF DENUDATION, UPHEAVAL, AND SUBSIDENCE IN REMODELLING THE EARTH'S

CRUST.

 

How we obtain an Insight at the Surface, of the Arrangement of Rocks at great

Depths.

Why the Height of the successive Strata in a given Region is so disproportionate

to their Thickness.

Computation of the average annual Amount of subaerial Denudation.

Antagonism of Volcanic Force to the Levelling Power of running Water.

How far the Transfer of Sediment from the Land to a neighbouring Sea-bottom may

affect Subterranean Movements.

Permanence of Continental and Oceanic Areas.

 

 

CHAPTER VIII.

 

CHRONOLOGICAL CLASSIFICATION OF ROCKS.

 

Aqueous, Plutonic, volcanic, and metamorphic Rocks considered chronologically.

Terms Primary, Secondary, and Tertiary; Palaeozoic, Mesozoic, and Cainozoic

explained.

On the different Ages of the aqueous Rocks.

Three principal Tests of relative Age: Superposition, Mineral Character, and

Fossils.

Change of Mineral Character and Fossils in the same continuous Formation.

Proofs that distinct Species of Animals and Plants have lived at successive

Periods.

Distinct Provinces of indigenous Species.

Great Extent of single Provinces.

Similar Laws prevailed at successive Geological Periods.

Relative Importance of mineral and palaeontological Characters.

Test of Age by included Fragments.

Frequent Absence of Strata of intervening Periods.

Tabular Views of fossiliferous Strata.

 

 

CHAPTER IX.

 

CLASSIFICATION OF TERTIARY FORMATIONS.

 

Order of Succession of Sedimentary Formations.

Frequent Unconformability of Strata.

Imperfection of the Record.

Defectiveness of the Monuments greater in Proportion to their Antiquity.

Reasons for studying the newer Groups first.

Nomenclature of Formations.

Detached Tertiary Formations scattered over Europe.

Value of the Shell-bearing Mollusca in Classification.

Classification of Tertiary Strata.

Eocene, Miocene, and Pliocene Terms explained.

 

 

CHAPTER X.

 

RECENT AND POST-PLIOCENE PERIODS.

 

Recent and Post-pliocene Periods.

Terms defined.

Formations of the Recent Period.

Modern littoral Deposits containing Works of Art near Naples.

Danish Peat and Shell-mounds.

Swiss Lake-dwellings.

Periods of Stone, Bronze, and Iron.

Post-pliocene Formations.

Coexistence of Man with extinct Mammalia.

Reindeer Period of South of France.

Alluvial Deposits of Paleolithic Age.

Higher and Lower-level Valley-gravels.

Loess or Inundation-mud of the Nile, Rhine, etc.

Origin of Caverns.

Remains of Man and extinct Quadrupeds in Cavern Deposits.

Cave of Kirkdale.

Australian Cave-breccias.

Geographical Relationship of the Provinces of living Vertebrata and those of

extinct Post-pliocene Species.

Extinct struthious Birds of New Zealand.

Climate of the Post-pliocene Period.

Comparative Longevity of Species in the Mammalia and Testacea.

Teeth of Recent and Post-pliocene Mammalia.

 

 

CHAPTER XI.

 

POST-PLIOCENE PERIOD, CONTINUED.-- GLACIAL CONDITIONS.

 

Geographical Distribution, Form, and Characters of Glacial Drift.

Fundamental Rocks, polished, grooved, and scratched.

Abrading and striating Action of Glaciers.

Moraines, Erratic Blocks, and "Roches Moutonnees."

Alpine Blocks on the Jura.

Continental Ice of Greenland.

Ancient Centres of the Dispersion of Erratics.

Transportation of Drift by floating Icebergs.

Bed of the Sea furrowed and polished by the running aground of floating Ice-

islands.

 

 

CHAPTER XII.

 

POST-PLIOCENE PERIOD, CONTINUED.-- GLACIAL CONDITIONS, CONCLUDED.

 

Glaciation of Scandinavia and Russia.

Glaciation of Scotland.

Mammoth in Scotch Till.

Marine Shells in Scotch Glacial Drift.

Their Arctic Character.

Rarity of Organic Remains in Glacial Deposits.

Contorted Strata in Drift.

Glaciation of Wales, England, and Ireland.

Marine Shells of Moel Tryfaen.

Erratics near Chichester.

Glacial Formations of North America.

Many Species of Testacea and Quadrupeds survived the Glacial Cold.

Connection of the Predominance of Lakes with Glacial Action.

Action of Ice in preventing the silting up of Lake-basins.

Absence of Lakes in the Caucasus.

Equatorial Lakes of Africa.

 

 

CHAPTER XIII.

 

PLIOCENE PERIOD.

 

Glacial Formations of Pliocene Age.

Bridlington Beds.

Glacial Drifts of Ireland.

Drift of Norfolk Cliffs.

Cromer Forest-bed.

Aldeby and Chillesford Beds.

Norwich Crag.

Older Pliocene Strata.

Red Crag of Suffolk.

Coprolitic Bed of Red Crag.

White or Coralline Crag.

Relative Age, Origin, and Climate of the Crag Deposits.

Antwerp Crag.

Newer Pliocene Strata of Sicily.

Newer Pliocene Strata of the Upper Val d'Arno.

Older Pliocene of Italy.

Subapennine Strata.

Older Pliocene Flora of Italy.

 

 

CHAPTER XIV.

 

MIOCENE PERIOD.-- UPPER MIOCENE.

 

Upper Miocene Strata of France.

faluns of Touraine.

Tropical Climate implied by Testacea.

Proportion of recent Species of Shells.

faluns more ancient than the Suffolk Crag.

Upper Miocene of Bordeaux and the South of France.

Upper Miocene of Oeningen, in Switzerland.

Plants of the Upper Fresh-water Molasse.

Fossil Fruit and Flowers as well as Leaves.

Insects of the Upper Molasse.

Middle or Marine Molasse of Switzerland.

Upper Miocene Beds of the Bolderberg, in Belgium.

Vienna Basin.

Upper Miocene of Italy and Greece.

Upper Miocene of India; Siwalik Hills.

Older Pliocene and Miocene of the United States.

 

 

CHAPTER XV.

 

LOWER MIOCENE.

 

Lower Miocene Strata of France.

Line between Miocene and Eocene.

Lacustrine Strata of Auvergne.

Fossil Mammalia of the Limagne d'Auvergne.

Lower Molasse of Switzerland.

Dense Conglomerates and Proofs of Subsidence.

Flora of the Lower Molasse.

American Character of the Flora.

Theory of a Miocene Atlantis.

Lower Miocene of Belgium.

Rupelian Clay of Hermsdorf near Berlin.

Mayence Basin.

Lower Miocene of Croatia.

Oligocene Strata of Beyrich.

Lower Miocene of Italy.

Lower Miocene of England.

Hempstead Beds.

Bovey Tracey Lignites in Devonshire.

Isle of Mull Leaf-Beds.

Arctic Miocene Flora.

Disco Island.

Lower Miocene of United States.

Fossils of Nebraska.

 

 

CHAPTER XVI.

 

EOCENE FORMATIONS.

 

Eocene Areas of North of Europe.

Table of English and French Eocene Strata.

Upper Eocene of England.

Bembridge Beds.

Osborne or St. Helen's Beds.

Headon Series.

Fossils of the Barton Sands and Clays.

Middle Eocene of England.

Shells, Nummulites, Fish and Reptiles of the Bracklesham Beds and Bagshot Sands.

Plants of Alum Bay and Bournemouth.

Lower Eocene of England.

London Clay Fossils.

Woolwich and Reading Beds formerly called "Plastic Clay."

Fluviatile Beds underlying Deep-sea Strata.

Thanet Sands.

Upper Eocene Strata of France.

Gypseous Series of Montmartre and Extinct Quadrupeds.

Fossil Footprints in Paris Gypsum.

Imperfection of the Record.

Calcaire Silicieux.

Gres de Beauchamp.

Calcaire Grossier.

Miliolite Limestone.

Soissonnais Sands.

Lower Eocene of France.

Nummulitic Formations of Europe, Africa, and Asia.

Eocene Strata in the United States.

Gigantic Cetacean.

 

 

CHAPTER XVII.

 

UPPER CRETACEOUS GROUP.

 

Lapse of Time between Cretaceous and Eocene Periods.

Table of successive Cretaceous Formations.

Maestricht Beds.

Pisolitic Limestone of France.

Chalk of Faxoe.

Geographical Extent and Origin of the White Chalk.

Chalky Matter now forming in the Bed of the Atlantic.

Marked Difference between the Cretaceous and existing Fauna.

Chalk-flints.

Pot-stones of Horstead.

Vitreous Sponges in the Chalk.

Isolated Blocks of Foreign Rocks in the White Chalk supposed to be ice-borne.

Distinctness of Mineral Character in contemporaneous Rocks of the Cretaceous

Epoch.

Fossils of the White Chalk.

Lower White Chalk without Flints.

Chalk Marl and its Fossils.

Chloritic Series or Upper Greensand.

Coprolite Bed near Cambridge.

Fossils of the Chloritic Series.

Gault.

Connection between Upper and Lower Cretaceous Strata.

Blackdown Beds.

Flora of the Upper Cretaceous Period.

Hippurite Limestone.

Cretaceous Rocks in the United States.