PRINCIPLES OF GEOLOGY -- BEING AN ATTEMPT TO EXPLAIN THE FORMER CHANGES OF THE EARTH'S SURFACE, BY REFERENCE TO CAUSES NOW IN OPERATION -- VOLUME III

by Charles Lyell, Esq., F.R.S.
For Sec. to the Geol. Soc., &c.
© 1990 The University of Chicago

Table of Contents:

• Front Matter
• Chapter 1:  Connexion between the subjects treated of in the former parts of this work and those to be discussed in the present volume – Erroneous assumption of the earlier geologists respecting the discordance of the former and actual causes of change – Opposite system of inquiry adopted in this work – Illustrations from the history of the progress of Geology of the respective merits of the two systems – Habit of indulging conjectures respecting irregular and extraordinary agents not yet abandoned – Necessity in the present state of science of prefixing to a work on Geology treatises respecting the changes now in progress in the animate and inanimate world
• Chapter 2:  Arrangement of the materials composing the earth's crust – The existing continents chiefly composed of subaqueous deposits – Distinction between sedimentary and volcanic rocks – Between primary, secondary, and tertiary – Origin of the primary – Transition formations – Difference between secondary and tertiary strata – Discovery of tertiary groups of successive periods – Paris basin – London and Hampshire basins – Tertiary strata of Bordeaux, Piedmont, Touraine, &c. – Subapennine beds – English crag – More recent deposits of Sicily, &c.
• Chapter 3:  Different circumstances under which the secondary and tertiary formations may have originated – Secondary series formed when the ocean prevailed: Tertiary during the conversion of sea into land, and the growth of a continent – Origin of interruption in the sequence of formations – The areas where new deposits take place are always varying – Causes which occasion this transference of the places of sedimentary deposition – Denudation augments the discordance in age of rocks in contact – Unconformability of overlying formations – In what manner the shifting of the areas of sedimentary deposition may combine with the gradual extinction and introduction of species to produce a series of deposits having distinct mineral and organic characters
• Chapter 4:  Chronological relations of mineral masses the first object in geological classification – Superposition, proof of more recent origin – Exceptions in regard to volcanic rocks – Relative age proved by included fragments of older rocks – Proofs of contemporaneous origin derived from mineral characters – Variations to which these characters are liable – Recurrence of distinct rocks at successive periods – Proofs of contemporaneous origin derived from organic remains – Zoological provinces are of limited extent, yet spread over wider areas than homogeneous mineral deposits – Different modes whereby dissimilar mineral masses and distinct groups of species may be proved to have been contemporaneous
• Chapter 5:  Classification of tertiary formations in chronological order – Comparative value of different classes of organic remains – Fossil remains of testacea the most important – Necessity of accurately determining species – Tables of shells by M. Deshayes – Four subdivisions of the Tertiary epoch – Recent formations – Newer Pliocene period – Older Pliocene period – Miocene period – Eocene period – The distinct zoological characters of these periods may not imply sudden changes in the animate creation – The recent strata form a common point of departure in distant regions – Numerical proportion of recent species of shells in different tertiary periods – Mammiferous remains of the successive tertiary eras – Synoptical Table of Recent and Tertiary formations
• Chapter 6:  Newer Pliocene formations – Reasons for considering in the first place the more modern periods – Geological structure of Sicily – Formations of the Val di Noto of newer Pliocene period – Divisible into three groups – Great limestone – Schistose and arenaceous limestone – Blue marl with shells – Strata subjacent to the above – Volcanic rocks of the Val di Noto – Dikes – Tuffs and Peperinos – Volcanic conglomerates – Proofs of long intervals between volcanic eruptions – Dip and direction of newer Pliocene strata of Sicily
• Chapter 7:  Marine and volcanic formations at the base of Etna – Their connexion with the strata of the Val di Noto – Bay of Trezza – Cyclopian isles – Fossil shells of recent species – Basalt and altered rocks in the Isle of Cyclops – Submarine lavas of the bay of Trezza not currents from Etna – Internal structure of the cone of Etna – Val di Calanna – Val del Bove not an ancient crater – Its precipices intersected by countless dikes – Scenery of the Val del Bove – Form, composition, and origin of the dikes – Lavas and breccias intersected by them
• Chapter 8:  Speculations on the origin of the Val del Bove on Etna – Subsidences – Antiquity of the cone of Etna – Mode of computing the age of volcanos – Their growth analogous to that of exogenous trees – Period required for the production of the lateral cones of Etna – Whether signs of Diluvial Waves are observable on Etna
• Chapter 9:  Origin of the newer Pliocene strata of Sicily – Growth of submarine formations gradual – Rise of the same above the level of the sea probably caused by subterranean lava – Igneous newer Pliocene rocks formed at great depths, exceed in volume the lavas of Etna – Probable structure of these recent subterranean rocks – Changes which they may have superinduced upon strata in contact – Alterations of the surface during and since the emergence of the newer Pliocene strata – Forms of the Sicilian valleys – Sea cliffs – Proofs of successive elevation – Why the valleys in the newer Pliocene districts correspond in form to those in regions of higher antiquity – Migrations of animals and plants since the emergence of the newer Pliocene strata – Some species older than the stations they inhabit – Recapitulation
• Chapter 10:  Tertiary formations of Campania – Comparison of the recorded changes in this region with those commemorated by geological monuments – Differences in the composition of Somma and Vesuvius – Dikes of Somma, their origin – Cause of the parallelism of their opposite sides – Why coarser grained in the centre – Minor cones of the Phlegraean Fields – Age of the volcanic and associated rocks of Campania – Organic remains – External configuration of the country, how produced – No signs of diluvial waves – Marine Newer Pliocene strata visible only in countries of earthquakes – Illustrations from Chili – Peru – Parallel roads of Coquirnbo – West-Indian archipelago – Honduras – East-Indian archipelago – Red Sea
• Chapter 11:  Newer Pliocene fresh – water formations – Valley of the Elsa – Travertins of Rome – Osseous breccias – Sicily – Caves near Palermo – Extinct animals in newer Pliocene breccias – Fossil bones of Marsupial animals in Australian caves – Formation of osseous breccias in the Mores – Newer Pliocene alluviums – Difference between alluviums and regular subaqueous strata – The former of various ages – Marine alluvium – Grooved surface of rocks – Erratic blocks of the Alps – Theory of deluges caused by paroxysmal elevations untenable – How ice may have contributed to transport large blocks from the Alps – European alluviums chiefly tertiary – Newer Pliocene in Sicily – Loss of the Valley of the Rhine – Its origin – Contains recent shells
• Chapter 12:  Geological monuments of the older Pliocene period – Subapennine formations – Opinions of Brocchi – Different groups termed by him Subapennine are not all of the same age – Mineral composition of the Subapennine formations – Marls – Yellow sand and gravel – Subapennine beds how formed – Illustration derived from the Upper Val d'Arno – Organic remains of Subapennine hills – Older Pliocene strata at the base of the Maritime Alps – Genoa – Savona – Albenga – Nice – Conglomerate of Valley of Magnan – Its origin – Tertiary strata at the eastern extremity of the Pyrenees
• Chapter 13:  Crag of Norfolk and Suffolk – Shown by its fossil contents to belong to the older Pliocene period – Heterogeneous in its composition – Superincumbent lacustrine deposits – Relative position of the crag – Forms of stratification – Strata composed of groups of oblique layers – Cause of this arrangement – Dislocations in the crag produced by subterranean movements – Protruded masses of chalk – Passage of marine crag into alluvium – Recent shells in a deposit at Sheppey, Ramsgate, and Brighton
• Chapter 14:  Volcanic rocks of the older Pliocene period – Italy – Volcanic region of Olot in Catalonia – Its extent and geological structure – Map – Number of cones – Scoriae – Lava currents – Ravines in the latter cut by water – Ancient alluvium underlying lava – Jets of air called 'Bufadors' – Age of the Catalonian volcanos uncertain – Earthquake which destroyed Olot in 1421 – Sardinian volcanos – District of the Eifel and Lower Rhine – Map – Geological structure of the country – Peculiar characteristics of the Eifel volcanos – Lake craters – Trass – Crater of the Roderberg – Age of the Eifel volcanic rocks uncertain – Brown coal formation
• Chapter 15:  Miocene period – Marine formations – Faluns of Touraine – Comparison of the Faluns of the Loire and the English Crag – Basin of the Gironde and Landes – Fresh-water limestone of Saucats – Position of the limestone of Blaye – Eocene strata in the Bordeaux basin – Inland cliff near Dax – Strata of Piedmont – Superga – Valley of the Bormida – Molasse of Switzerland – Basin of Vienna – Styria – Hungary – Volhynia and Podolia – Montpellier
• Chapter 16:  Miocene alluviums – Auvergne – Mont Perrier – Extinct quadrupeds – Velay – Orleanais – Alluviums contemporaneous with Faluns of Touraine – – Miocene fresh – water formations – Upper Val d'Arno – Extinct mammalia – Coal of Cadibona – Miocene volcanic rocks – Hungary – Transylvania – Styria – Auvergne – Velay
• Chapter 17:  Eocene period – Fresh-water formations – Central France – Map – Limagne d'Auvergne – Sandstone and conglomerate – Tertiary Red marl and sandstone like the secondary 'new red sandstone' – Green and white foliated marls – Indusial limestone – Gypseous marls – General arrangement and origin of the Travertin – Fresh-water formation of the Limagne – Puy en Velay – Analogy of the strata to those of Auvergne – Cantal – Resemblance of Aurillac limestone and its flints to our upper chalk – Proofs of the gradual deposition of marl – Concluding remarks
• Chapter 18:  Marine formations of the Eocene period – Strata of the Paris basin how far analogous to the lacustrine deposits of Central France – Geographical connexion of the Limagne d'Auvergne and the Paris basin – Chain of lakes in the Eocene period – Classification of groups in the Paris basin – Observations of M. C. Prevost – Sketch of the different subdivisions of the Paris basin – Contemporaneous marine and fresh-water strata – Abundance of Cerithia in the Calcaire grossier – Upper marine formation indicates a subsidence – Part of the Calcaire grossier destroyed when the upper marine strata originated – All the Parisian groups belong to one great epoch – Microscopic shells – Bones of quadrupeds in gypsum – In what manner entombed – Number of species – All extinct – Strata with and without organic remains alternating – Our knowledge of the physical geography, fauna, and flora of the Eocene period considerable – Concluding remarks
• Chapter 19:  Volcanic rocks of the Eocene period – Auvergne – Igneous formations associated with lacustrine strata – Hill of Gergovia – Eruptions in Central France at successive periods – Mont Dor an extinct volcano – Velay – Plomb du Cantal – Train of minor volcanos stretching from Auvergne to the Vivarais – Monts Domes – Puy de Côme – Puy Rouge – Ravines excavated through lava – Currents of lava at different heights – Subjacent alluviums of distinct ages – The more modern lavas of Central France may belong to the Miocene period – The integrity of the cones not inconsistent with this opinion – No eruptions during the historical era – Division of volcanos into ante-diluvian and post-diluvian inadmissible – Theories respecting the effects of the Flood considered – Hypothesis of a partial flood – Of a universal deluge – Theory of Dr. Buckland as controverted by Dr. Fleming – Recapitulation
• Chapter 20:  Eocene formations, continued – Basin of the Cotentin, or Valognes – Rennes – Basin of Belgium, or the Netherlands – Aix in Provence – Fossil insects – Tertiary strata of England – Basins of London and Hampshire – Different groups – Plastic clay and sand – London clay – Bagshot sand – Fresh-water strata of the Isle of Wight – Palaeotherium and other fossil mammalia of Binstead – English Eocene strata conformable to chalk – Outliers on the elevated parts of the chalk – Inferences drawn from their occurrence – Sketch of a theory of the origin of the English tertiary strata
• Chapter 21:  Denudation of secondary strata during the deposition of the English Eocene formations – Valley of the Weald between the North and South Downs – Map – Secondary rocks of the Weald divisible into five groups – North and South Downs – Section across the valley of the Weald – Anticlinal axis – True scale of heights – Rise and denudation of the strata gradual – Chalk escarpments once sea-cliffs – Lower terrace of 'firestone,' how caused – Parallel ridges and valleys formed by harder and softer beds – No ruins of the chalk on the central district of the Weald – Explanation of this phenomenon – Double system of valleys, the longitudinal and the transverse – Transverse how formed – Gorges intersecting the chalk – Lewes Coomb – Transverse valley of the Adur
• Chapter 22:  Denudation of the Valley of the Weald, continued – The alternative of the proposition that the chalk of the North and South Downs were once continuous, considered – Dr. Buckland on the Valley of Kingsclere – Rise and denudation of secondary rocks gradual – Concomitant deposition of tertiary strata gradual – Composition of the latter such as would result from the wreck of the secondary rocks – Valleys and furrows on the chalk how caused – Auvergne, the Paris basin, and south-east of England one region of earthquakes during the Eocene period – Why the central parts of the London and Hampshire basins rise nearly as high as the denudation of the Weald -- Effects of protruding force counteracted by the levelling operations of water – Thickness of masses removed from the central ridge of the Weald – Great escarpment of the chalk having a direction north-east and south-west – Curved and vertical strata in the Isle of Wight – These were convulsed after the deposition of the fresh-water beds of Headen Hill – Elevations of land posterior to the crag – Why no Eocene alluviums recognizable – Concluding remarks on the intermittent operations of earthquakes in the south-east of England, and the gradual formation of valleys – Recapitulation
• Chapter 23:  Secondary formations – Brief enumeration of the principal groups – No species common to the secondary and tertiary rocks – Chasm between the Eocene and Maestricht beds – Duration of secondary periods – Former continents placed where it is now sea – Secondary fresh-water deposits why rare – Persistency of mineral composition why apparently greatest in older rocks – Supposed universality of red marl formations – Secondary rocks why more consolidated – Why more fractured and disturbed – Secondary volcanic rocks of many different ages
• Chapter 24:  On the relative antiquity of different mountain-chains – Theory of M. Elie de Beaumont – His opinions controverted – His method of proving that different chains were raised at distinct periods – His proof that others were contemporaneous – His reasoning why not conclusive – His doctrine of the parallelism of contemporaneous lines of elevation – Objections – Theory of parallelism at variance with geological phenomena as exhibited in Great Britain – Objections of Mr. Conybeare – How far anticlinal lines formed at the same period are parallel – Difficulties in the way of determining the relative age of mountains
• Chapter 25:  On the rocks usually termed 'Primary' – Their relation to volcanic and sedimentary formations – The 'primary' class divisible into stratified and unstratified – Unstratified rocks called Plutonic – Granite veins – Their various forms and mineral composition – Proofs of their igneous origin – Granites of the same character produced at successive eras – Some of these newer than certain fossiliferous strata – Difficulty of determining the age of particular granites – Distinction between the volcanic and the plutonic rocks – Trappean rocks not separable from the volcanic – Passage from trap into granite – Theory of the origin of granite at every period from the earliest to the most recent
• Chapter 26:  On the stratified rocks usually called 'primary' – Proofs from the disposition of their strata that they were originally deposited from water – Alternation of beds varying in composition and colour – Passage of gneiss into granite – Alteration of sedimentary strata by trappean and granitic dikes – Inference as to the origin of the strata called 'primary' – Conversion of argillaceous into hornblende schist – The term 'Hypogene' proposed as a substitute for primary – 'Metamorphic' for 'stratified primary' rocks – No regular order of succession of hypogene formations – Passage from the metamorphic to the sedimentary strata – Cause of the high relative antiquity of the visible hypogene formations – That antiquity consistent with the hypothesis that they have been produced at each successive period in equal quantities – Great volume of hypogene rocks supposed to have been formed since the Eocene period – Concluding remarks
• Relative Ages of Different Formations
• Deshay's Table of Shells
• General Results
• Fossil Shells Collected by the Author
• Glossary
• Index

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