Geology : physical and historical

Front matter

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Esstrimnrysttarinsstt

7 eS sere ne peiesiaeios

Preface

In the preparation of this book, an attempt has been made to present an outline of the essentials of modern geology. By avoiding all details not necessary to an understanding of the fundamental principles of the science, it is hoped that this work will prove interesting to the student, although not less accurate because interesting. In the section on physical geology the human relation has been emphasized whenever possible, while in the historical section the history of life from the evolutionist’s point of view has been taken up in broad outline.

Much that may prove excellent in this work is due to the help ofa number of eminent geologists, whose suggestions and criticisms have added many interesting points and have assisted in the elimination of errors.

The writer wishes especially to express his debt to Dr. W. D. Matthew, of the American Museum of Natural History, City of New York; to Professor Joseph Barrell, of Yale University; and to Professor A. W. Grabau, of Columbia University, upon whom he has freely called for suggestions and criticisms and from whom much valuable assistance has been received.

One or more chapters have also been read and helpfully criticized by the following geologists and educators, and their generous aid is acknowledged with keen appreciation: Messrs. H. E. Gregory, of Yale University; C. K. Schwartz, of Johns Hopkins University ; J. B. Woodworth, of Harvard University; J. S. Grasty, of the University of Virginia; N. M. Fenneman, of the University of Cincinnati; Sumner W. Cushing, of the Salem (Massachusetts) Normal School; J. W. Gidley and C. W. Gilmore, of the United States National Museum; T. W. Stanton and F. H. Knowlton, of the United States Geological Survey; Charles Schuchert and G. G. Mac- Curdy, of Yale University; T. D. A. Cockerell, of Boulder, Colorado ; L. Hussakof, of the American Museum of Natural History; E. C. Case, of the University of Michigan; O. P. Hay, of the Carnegie

6 PREFACE

Institution of Washington ; Sidney Powers, Cambridge, Massachusetts ; and C. L. Dake, of the Missouri School of Mines.

For suggestions as to the most characteristic species of the vari- _ ous periods, credit is due to Professor G. D. Harris, for the Tertiary ; Messrs. T. W. Stanton and F. H. Knowlton, for the Mesozoic; and Drs. R. Ruedemann and E. M. Kindle, and Mr. L. Burling, for the Paleozoic.

The numerous block diagrams which illustrate the text were made in wash rather than in line because the former are not only more attractive in appearance, but because being more realistic, they are more readily understood by the student. These drawings and many of the diagrams which illustrate the text are the work of Mr. G. S. Barkinton, to whom much credit is due.

The writer is greatly indebted to Professors H. F. Osborn, W. B. Scott, F. A. Lucas, and S. W. Williston, for permission to use photographs of restorations of extinct animals, made by them or under their direction, and to Professor William Bullock Clark and Dr. John M. Clarke for the loan of a number of original drawings of the Geological Surveys of which they are directors.

Chapter I

WEATHERING MECHANICAL AGENCIES : ‘ ; d A ; - : “ r y Frost. Talus. Rock Glaciers. Creep of Soils. Changes in Daily Temperature. Mechanical Action of Animals and Plants. Rain. Wind. Lightning.

CHEMICAL AGENCIES . 5 : ‘ ; ‘ q A ; ; : = ; : Solution. Oxidation. Hydration. Carbonation. Organisms. Comparison of Effects of Chemical and Mechanical Weathering. RESULTS OF WEATHERING . : ‘ : : ; , | Spheroidal Weathering. Differential Weathering. onndenng of Valleys. Rock Mantle and Soil. Kinds of Soil. Removal of Soil.

CHAPTER IT

WORK OF THE WIND WIND AND SAND j 5 : , Wind without Bands Wind ith Sandi Sand ae Shape and Origin of Dunes. Migration of Sand Dunes. Beneficial Effect of Dunes. Material of Dunes. Height of Dunes. Eolian Sandstone. Dust. Loess.

Chapter II

THE WORK OF GROUND WATER Work OF Grounp WATER 4 F ; : : : 3 ; t , ‘Quantity of Ground Wate The Water Table. Wells. Movement of Ground Water. Depth of Ground Water. Artesian Wells. Chemical Work of Ground Water. Solution. Replacement and Deposition. Belts of Weathering and Cementation. Desert Limestone. Mechanical Work of Ground Water.

SPRINGS : : : : : . : : F : Z : 5 Origin of Gitiams: Constant and Intermittent Springs. Mineral Matter in Spring Water. Mineral Springs. Temperature of Springs. Thermal Springs. Geysers.

PAGE ar

: PAGE SrrIKING EFFECTS OF GROUND WATER. ‘ - s s : 3 e 4 i 69 Swallow Holes. Caverns. Natural Bridges. Cave Deposits. Karst.

Landslides.

CONCRETIONS . e i ; ’ * 5 rs 4 5 eS Composition oF Gencrecions: Time of Formation. Odlitic Limestone. Geodes.

CHAPTER IV THE WORK OF STREAMS ERACTORS IN STREAM EROSION . © «fo ) | 3), (G0: ” 5 = VCO eine gam rte Ca Material Carried by Streams. How the Sediment is Moved. Factors Determining the Velocity of Streams. Water Wear. Solution. Vertical Erosion (Corrasion). Weathering and Vertical Erosion. . Base Level of Erosion. Effect of Load. Factors Affecting the Rate of Erosion. Scour and Fill. Lateral Erosion.

Features DvuE TO STREAM EROSION . » 89 Falls and Rapids. Exceptions —— Palle not hte Result ae restos ‘Pots holes. Canyons. Instances of Rapid Erosion. Effect of Deforestation on Rivers. Growth of Valleys. Valleys Formed in Ways Other than by Stream Erosion. The Direction of Valleys. Basins and Divides. Elevations Due to Unequal Hardness. Outliers. Rock Terraces. Stream Piracy.

THE ErRosIoN CYCLE. ; : : , = a z Z : . ‘ : « -¥oq Youth. Maturity. Old Age. Effect of Elevation and Depression on Streams.

PENEPLANATION : 114 The Peneplain of Soucheen iNew Encland, The Aepaackion Peneplae The Laurentian Peneplain. Rate of the Denudation of Continents. How the Load of Streams is Measured.

DEPOSITION 2 : a . : . ‘ < E : - “ «. bes

Causes of Papestion: Flood Plains. Meanders. Oxbow Lakes. Natural Levees. Alluvial Cones and Fans. Piedmont or Alluvial Plains. Alluvial Terraces. Discontinuity of Terraces. Characteristics of River Deposits.

Growth of Deltas: Structure of Deltas.

DEPOSITION IN LAKES BY STREAMS AND BY OTHER AGENTS . a «.. £33

Mechanical Deposits. Chemical Deposits. Organic Deposits = Distant Marl. Peat. Playas. Salt Lakes. Alkaline Lakes. Origin of Rock Salt. Extinct Lakes.

CHAPTER V

THE WORK OF GLACIERS GENERAL CONSIDERATIONS , +. 0 @ ee.) ee eee «45 Distribution and Size of Cincest Position of the Snow Line. Formation of Ice in Snow Fields.

CONTENTS

MOunrTAIN GLACIERS . ‘ : ; Z A ; : F “ ; : ‘ Formation. Cirques. Origin of Cirques. Development of Cirques. Fate of Cirques. Ablation.

SURFACE oF MounrAIN GLACIERS 2 - ‘ : : ; : : : Irregularities Dueto Tension. Irregularities Due to Streams and Ice Tables.

MOVEMENT OF GLACIERS . ‘ ; : 5 : : : : : ; = Rate of Movement. Differential Movement of Glaciers. Factors Influencing the Rate of Movement. Lower Limit of Glaciers.

TRANSPORTATION OF MOUNTAIN GLACIERS E , 5 . , Surface Moraines. Subglacial Material. Englacial Material.

Erosion BY MOUNTAIN GLACIERS ; ; é 2 : : : F : Plucking and Abrasion. Effect on the Material Carried. Factors Influencing the Rate of Erosion.

Deposits oF Mountain GLACIERS S00 ee ee “av eee Terminal Moraines. Submarginal Morawean. Ground Moraine. The Work of Glacial Streams.

LANDSCAPE MopiFrep By GLAcrAL ACTION : : , : : 4 : : Characteristics of Glaciated Valleys. Mature Glaciated Valleys. Destruction of Features of Glaciated Valleys. Fiords.

PIEDMONT GLACIERS .

CONTINENTAL IcE SHEETS F & : 5 : 3 .

Greenland. The Antarctic Connent

ANCIENT GLACIATION DEPOSITION . : : “ é : ‘ 5 A : : ‘ : : : Bowlders. Unstratified Drift. Moraines. Terminal Moraines. Moraines of the Last Great Ice Sheet in North America. Ground Moraine. Drumlins. Stratified Drift. Outwash Plains. Terraces. Deltas. Eskers. Kames. Relation between Stratified and Unstratified Drift.

EROSION BY CONTINENTAL GLACIERS ; Effect on the Underlying Rock. Bedikcation | in the Shane of he Hills. Effect of Glaciation on Drainage. Lakes and Ponds. Rivers.

ICEBERGS : : : : é ; : Formation of es Size and Work of Icebergs.

GLACIAL MOVEMENT . z : : : : Viscosity Theory. Expansion and Gonrraction. Regelation. Melting and Pressure. Growth of Granules.

CHAPTER VI THE OCEAN AND ITS WORK

GENERAL CHARACTER OF THE OCEAN ; : 2 : £ : : : ; Topography of the Ocean Floor. Irregularities of the Ocean Floor. Composition of Ocean Water. Temperature of the Ocean. Distribution

of Marine Life. Age of the Ocean.

167 168

MOVEMENT OF THE WATER. : 3 P : He ti ae Wave Motion. The Bika of Mise: Force of Storm Waves. Height of Storm Waves. Tides. Tidal Currents. Tidal Bores. Earthquake

Waves. Ocean Currents.

MarRINE EROSION . : a Bey é - - : & 4 Factors in Marine ronon. Shore Ice. Ice in Lakes.

Resutts OF MARINE EROSION . : A Z é . ‘ Effect of Erosion on Different Marcas. Influence of Joints and Other Planes on Erosion. Coves and Headlands. Sea Caves and Blow-

holes. Arches. Stacks. Marine Terraces. Striking Examples of

Marine Erosion. Sea-captured Streams. Raised Beaches. Ancient

Plains of Marine Denudation. The New England Marine Plain.

TRANSPORTATION é , ‘ Littoral or Shore Curredhe Tidal Currents.

FEATURES RESULTING FROM TRANSPORTATION . 3 : 2 : , é - Beaches. Bayhead Beaches. Bars and Shire. Sand Reefs or Barrier Beaches. Tied Islands. Examples of the Constructive Work of the

Sea.

Smooth Shorell Cuestas. Rough Shores. Examples of Irregular Coasts. Proofs of Elevation and Depression. The Stability of the Atlantic Coast of North America. Cycle of Shore Erosion.

DEPOSITION IN SEAS AND LAKES . ; : : 3 5 3 Source and Extent of Land-derived Shasrones Stratification. Cross or

False Bedding.

LitroraAL DEPosITS : . ; - : 5 A 2 Extent. Character of Littoral Derdian’ Distinguishing Characteristics of Littoral Deposits.

SHOAL-WATER DEPOSITS : : ‘ < : A < ; = Extent and Character oF Desa Limestone. Lens-shaped Sediments. Dovetailing of Sediments. Basal Conglomerates. Subsidence Neces-

sary for Great Accumulations.

Blue Mud. Globigerina Gere Radiolarian Ooze. Red Clay.

CoraL REEFS AND ISLANDS ‘ : : 7 - : : F = 5 . Coral-reef Problem. Subsidence Theory of Darwin. Submarine Bank Theory of Murray and Others. Change in Sea Level Due to Glaciation,

or the Glacial-control Theory.

CONSOLIDATION OF SEDIMENTS . F : : Z . f . 7 = Cementation. Effect of Preure? Effect of Heat.

CLASSIFICATION OF SEDIMENTARY ROCKS . r R 5 . ‘ < 7 Limestones. Sandstones. Shales. Deposits in Lakes and Deserts. Influence of Sedimentary Rocks upon Topography.

PAGE 198 ies

CONTENTS

CHAPTER VII THE STRUCTURE OF THE EARTH

STRUCTURAL FEATURES OF Rocks Dip and Strike. Effect of Dip and Bcnike | upon HOutison.

Foips 5 5 : Effect of Haidine - on Competent ane Tncoraperene ‘Strats, How the Structure of a Region is Determined. Origin of Folds. Warping.

Zones of Flow and Fracture.

Jornts é : . fi ‘ , : Origin of Tornes. Effect of Joints on Topography. FAvuLts : ; : ; : ; ; 5 ; ~ Normal or aGraviey Fanles.. Examples of Normal Faults. Reverse or Thrust Faults. Examples of Thrust Faults. Vertical and Horizontal Faults. Influence of Faults on Topography. Minor Features of a Fault Fracture. Detection of Faults. Origin of Faults. Rapidity of Fault Movements.

CoNFORMITY AND UNCONFORMITY APA Importance of Unconformities. Overlap.

CONSTITUTION OF THE EARTH’S INTERIOR Zone of Variable Temperature. The Tater ae of he Barth.

THEORIES OF THE PHYSICAL STATE OF THE EARTH’S INTERIOR : . : : Internal Fluidity Theory. Solid Interior. Gaseous Center. Radioactivity and a Solid Center. Subcrust Theory. Summary.

CHAPTER VIII

EARTHQUAKES AND ATTENDING FEATURES ; : F : ‘ ‘ : . The San Francisco Earthquake. Distribution of Earthquakes. Summary of the Causes of Earthquakes. Displacements. Depth of the Plane or Point of Origin. Earthquake Waves. Amplitude of Vibration. Vorticose and Twisting Movements. Duration. Frequency. Areas Affected by Certain Earthquakes. Instruments for Determining and

Measuring Earthquakes.

EFFECTS OF EARTHQUAKES - 3 : ; . ‘ F : ‘ - 5

Faults and Fissures. Changes in Level. Landslides. Earthquake Topography. Sounds. Loss of Life. Effect on Underground Water. Gases. Construction of Buildings in Earthquake Regions. Effect of Earthquakes on the Sea. Evidence that a Region has been Free from Severe Earthquakes.

CHAPTER IX

VOLCANOES AND IGNEOUS INTRUSIONS VOLCANOES. Pee A. CA) | = ey © Sy eee acne How Wolcanves. Besitt New Volcanoes. Classification of Volcanoes.

Lig |

PAGE

MareRIALts ERUPTED . c 4 : ° fe 5 3 3 F 2 ; Gases. Fragmental Riacenales Lava. LavaStreams. Effect of Composition on Fluidity. Temperature. Surface of Lava Flows. Velocity

of Lava Flows. Nature of Lavas.

Types or VOLCANOES c ; j ‘ : ; ; ‘

The Explosive or Faun Type: Vesuvius. Krakatao. Katmai. Mt. Pelée. Bandai-san.

The Quiet or Hawaiian Type: Crater of Kilauea. Eruptions. Lava Streams. Origin of Calderas. Steep Lava Cones: Volcanoes of the Chimborazo Type.

Fissure Eruptions: Recent Icelandic Lava Sheets.

CHARACTERISTICS OF VOLCANIC CONES h f ; ee / ; Profiles of Volcanoes. Shape of Chane Erosion of Volcanic Cénes. Necks and Plugs. Age of Volcanoes in the United States.

DISTRIBUTION AND NUMBER OF VOLCANOES . y - A a ‘ E

Number of Volcanoes. Distribution. Cause of Distribution. Ancient Volcanoes.

ImMporTANCE OF VOLCANISM TO MAN 3 A “ a : ‘ F é “

Beneficial Effects. Harmful Effects. Volcanoes and Climate.

SUBORDINATE VOLCANIC PHENOMENA 3 F é P : : > f . iz Mud Volcanoes. Solfataras.

INTRUSIVE OR PLuTONIC ROCKS 3 : 4 “ Injected Masses: Dikes. Sills. Laccoliths.

Subjacent Masses: Stocks. Batholiths. Some Effects of Intrusions.

IGNEOUS ROCKS . ‘ é 3 P Subdivisions escndive ipa Chemital Cancion *Subdivizions Depending upon Texture.

CLASSIFICATION OF IGNEOUS ROCKS . = : - : 3 > : : FE Coarse-grained Igneous Rocks: Granite. Syenite. Diorite. Gabbro. Peridotite.

Compact or Fine-grained Igneous Rocks: Felsites. Basalts. Glassy Rocks: Obsidian or Volcanic Glass. Pitchstone.

FRAGMENTAL VOLCANIC ROCKS . ; 3 : - - 3 FE - : . : Tuff. Volcanic Breccia. Columnar Structure of Lava.

AGE oF IcNEouS Rocks . ; . 3 P . = . é ‘ é .

THEORIES OF VOLCANISM . - : . °

Theory Based upon the Peuanien that the ota 15 ; Molten.

Theories Based upon the Assumption that the Earth is Solid: Heat by Friction. Formation of Lava Reservoirs by Relief of Pressure. Liquid-thread Theory.

Abyssal Injection Hypothesis.

RESUME oF PRESENT KNOWLEDGE OF VOLCANISM . 5 :

Origin of Volcanic Gases. Cause of the ecenson a hag Beatie of Periodicity. Influences of the Atmosphere, etc.

334 334

.

CONTENTS

CHAPTER X ee

Kinps oF METAMORPHISM ; ; Contact Metamorphism. Regional

CLASSIFICATION OF METAMORPHIC. ROCKS

Quartzite. Marble. Slate. Schist. Gnoiss:

SUMMARY OF CAUSES OF METAMORPHISM Heat. Moisture. Pressure.

ARRANGEMENT OF MINERALS

Crystallization. Granulation: Relation of Cleavage to Pressure. From Igneous, through Sedimentary, to Metamorphic Rocks. Weathering of

Metamorphism.

Metamorphic Rocks. Economic Importance.

CHAPTER XI

MOUNTAINS CLASSIFICATION OF MOUNTAINS

Mountains of Accumulation. Residual Mountains. Fault or Block Mountains. Laccolith Mountains.

Mountains.

AND PLATEAUS

Domed Mountains. Complexly Folded

ORIGIN AND DEVELOPMENT OF FoLtDED MOounrtaINs ; : ; ; : : Geosynclines. Lateral Pressure. Experiments in Mountain Building.

Rate of Folding. To What the

Topographic Features of Folded Mountains are Due. Cycle of Erosion of Mountains.

THEORIES OF MouNTAIN BUILDING .

Cause of Lateral Pressure. The Piewtion of Pistdaus ad Mountains. The Theory of Isostasy. The Distribution of Mountains. Permanence of Continents and Ocean

Basins. Age of Mountains.

CHAPTER XII

ORE DEPOSITS

CHARACTERISTICS OF DEPOSITS .

Ores in Ready-made Cavities. Fissure Deposits. Form and Extent of

Veins. Source of Vein Material. Cause of Precipitation. Replacement Deposits. Weathering and Concentration of Ores. Magmatic Segregation. Placer Gold Deposits. Sedimentary Iron Deposits.

Part II. Historical Geology Chapter XIII

FossIts . ; 5 , : : The Original Substance may be Molds. Footprints, Trails, etc.

Imperfection of the Record.

Preserved. Replacement. Casts and Entombment of Plants and Animals.

PAGE 341

344 347

PAGE GEOLOGICAL CHRONOLOGY NM : 0 3 . é F . 4 : . » BSE Order of Superposition. Chronology Determined by Fossils. Use of Fossils in Determining Physical Conditions. Difficulties in Corre-

lating Strata.

Divisions oF GEOLOGICAL TIME . . ‘ - = : - * * F ‘ wo ESS:

CHAPTER XIV THE EARTH BEFORE THE CAMBRIAN

THEORIES OF THE Eartu’s ORIGIN . : z , C - 85 Nebular Hypothesis. Planetesimal Hiyporheais. Nebular and Planetesimal Theories Contrasted.

PreE-CAMBRIAN ERAS . : é i 2 4 S : . . . > - 388 Tue ArcH#ozoic ERA. . i ‘4 ‘ 5 bE rl oy 3855 Distribution of the Aethsonor Reve ‘Charactorietics of Archzozoic Rocks.

Thickness. Causes of Metamorphism and Deformation. Conditions during the Archewozoic Era. Duration. Bearing upon the Theories of the Earth’s Origin.

THE Proterozoic ERA. 5 A : - z z : 2 883 Archeozoic and Picteroceic: Caueeaseed: By Proterozoic in Different Regions. Iron and Copper Deposits. Life of the Proterozoic Era. Duration. Climate. Life before Fossils.

CHAPTER XV THE CAMBRIAN PERIOD

Tue PaLeozoic ERA . x : 5 ° ‘ - = 3 s . 2 . « 1408 THE CAMBRIAN PERIOD . : : A ‘ . 2 fs ‘ s 3 a - 4b2 Divisions of the Cambrian. Location of Cambrian Rocks. Physical

Geography of Ancient Periods. Basal Unconformity. Physical Geography of the Cambrian. Character of the Cambrian Rocks. Present Condition of the Sediments. Volcanism. Close of the Cambrian. Other Continents.

Lire oF THE CAMBRIAN . ‘ . C : P > = : < a ‘ - 408 PLANTS a sie ae eee Me mer ANIMALS. z : : = ‘ H : . . . . e . . - 410 Crustacea: Trilobites. Other Crustaceans.

Mollusca: Gastropods.

Molluscoidea: Brachiopods.

Echinodermata: Cystoids.

Worms.

Celenterata: Corals. Graptolites. Jellyfish. Sponges. Protozoa.

SUMMARY. 5 : ‘ s P - : - 416 Evolution duting the Cinkran: “Chinate and Duration.

CONTENTS IS

CHAPTER XVI THE ORDOVICIAN PERIOD

PAGE ORDOVICIAN PHysicaL GEOGRAPHY . ; : : ; , d : ‘ ; AS, Close of the Ordovician. Cincinnati Anticline. Volcanism. Ordovician of Other Continents.

PETROLEUM AND NATURAL GAS z : Z ‘ - . - : F 5 Srey Conditions Favoring the Accumulation of Oil and Gas. Origin of Oil and Gas. Life of Oil Wells and Fields.

LIFE OF THE ORDOVICIAN . ‘ . , js ‘ = 5 : ; 5 » 427 Protozoa.

Celenterata: Sponges. Graptolites. Stromatopora. Corals. Echinodermata: Cystoids. Crinoids. Blastoids, Starfish, Brittle Stars, and Sea Urchins.

Molluscoidea: Brachiopods. Bryozoa.

Mollusca: Pelecypods. Gastropods. Cephalopods. Crustacea: Trilobites. Other Arthropods.

Fishes.

PLANTS : : : i ‘ ‘ : ‘ : A A ; 4 " - 436 Seaweeds.

SUMMARY . 5 ; ‘ 5 : , e : ; : : : ; - 436 i Progress and Character of Ordovician Life. Climate and Duration of the Ordovician.

CHAPTER XVII

THE SILURIAN PERIOD SILURIAN PHysICAL GEOGRAPHY 7 : ; : = . : s ; 5 0) Geography of the Silurian. Character and Thickness of the Sediments. Clinton Iron Ore. Deserts. Origin of Rock Salt. Igneous Rocks. Other Continents.

LIFE OF THE SILURIAN. ; : : : : . : 4 : 5 : - 444 Celenterata: Corals. Other Ceelenterates.

Echinodermata: Crinoids. Cystoids.

Molluscoidea: Brachiopods. Bryozoa.

Mollusca: Gastropods. Pelecypods. Cephalopods. Arthropoda: Trilobites. Eurypterids. Scorpions. Fishes.

SUMMARY . 3 7 ; 5 : a : : ‘ : 3 % ‘ 3 - 450 Life on the Land. Migration. Climate and Duration. Close of the Silurian. CHAPTER XVIII THE DEVONIAN PERIOD DEVONIAN PHYSICAL GEOGRAPHY . ‘ a 3 i ‘ z s F : «6452 Subdivisions of the Devonian. Geography. The Devonian in New York. Continent of Appalachia. Igneous Rocks. Devonian Oil and Gas. Devonian of Other Continents. eIReROn. Trey DEVONIAN est tsk 4 5y+. 8s eo ees tM eee | wt a SO Celenterata: Corals.

CLELAND GEOL. — 2

Echinodermata: Crinoids. Blastoids.

Molluscoidea and Mollusca: Brachiopods. Bryozoans. Pelecypods. Gastropods. Cephalopods.

Arthropoda: Trilobites. Barnacles. Eurypterids. Insects.

Fishes; Ostracoderms. Sharks. Lungfish. Ganoids. Teleosts or Bony Fish. Comparison of Devonian and Modern Fish. Why the Verte- ‘brate Type was “ Fit.””

_ SUMMARY ‘ ‘ : : : : ; ; ‘ Migration and Evolution. Climate and Duration.

CHAPTER XIX

THE CARBONIFEROUS PERIODS MISSISSIPPIAN OR LOWER CARBONIFEROUS .

Close of the Mississippian. Other Continents. PENNSYLVANIAN OR UppPeR CARBONIFEROUS Coat Fretps or Norta AMERICA . ; ; ; 5 ‘ : 7 : ; = Productive Coal Fields: Eastern Canadian and New England Fields. Appalachian Field. Michigan Coal Field. The Indiana-Illinois Field. The Iowa-Missouri-Texas Field.

SUMMARY OF THE PENNSYLVANIAN ene Iron and Oil. Duration. Other Continents.

PERMIAN ; : 5 ; ; 4 . x : ‘ . 4 5 : Permian “Glaciation. Permian Deserts. Igneous Activity. Appalachian Deformation. Age of the Deformation. Other Continents. INVERTEBRATES OF THE CARBONIFEROUS i) aa OR ee aes ee Protozoans. Ccelenterates and Echinoderms. Mbolluscoids. Mollusks. Arthropods. Insects.

VERTEBRATES OF THE CARBONIFEROUS ‘ : : . : 3 ‘ % “ Fishes. Amphibians. Origin of Amphibians. Rise of Amphibians. Reptiles. Rise of Reptiles.

CaRBONIFEROUS PLANTS ‘ y A = - : 2 e : ‘ : Ancestral Ferns and Seed Ferns. Club Mosses (Lycopods). Sphenophylls. Horsetails (Calamites). Cordaites and Other Gymnosperms. Conditions under which the Coal Plants Grew. GOAL, 2 , ; , : , : : ‘ ; : ; . : : - Mode of Occurrence. Origin of Coal. Necessary Conditions for Coal Formation. How Vegetable Tissue Accumulated. How it was Kept from Decay. How it was Changéd to Coal and What Varieties Resulted. Conditions Favoring Coal Formation in the Pennsylvanian. Extent and Structure of Coal Beds. Climate during the Deposition of Coal.

PROBLEMS OF THE PERMIAN SUMMARY OF THE PALEOozorc ERA 5 . : F : : F . Z The Building of the Continents. Evolution and Extinction of Life. Climate.

PAGE

407 407

504 505 es CHAPTER XX THE MESOZOIC ERA: THE AGE OF REPTILES

, PAGE SUBDIVISIONS OF THE Mrsozoic A 5 ‘i 3 ’ . 5 Z “ - 508 PHYSICAL GEOGRAPHY DURING THE MEsozoIc . é A 4 : ° - : . 508 Triassic. 508

Atlantic and Gulf Coasts. Western Interior. Pacific Coast. Triassic in Other Continents.

JURASSIC. > 2. 7°, ‘ i 3 . : . . : : ; Pr : + §12 Atlantic and Gulf Coasts. Western Interior. Mountain Forming in the West. Jurassic of Other Continents.

Lower Cretaceous (CoMANCHEAN) P : Z P : : - . : saa Atlantic and Gulf Coasts. Western Interior. Pacific Coast. Lower Cretaceous of Other Continents.

Upper CRETACEOUS (CRETACEOUS) . 2 - : : : : ae 5 ny SLO Atlantic and Gulf Coasts. Pacific Coast. Western Interior. Upper Cretaceous of Other Continents. The Cretaceous Peneplain. . Mountain-making Movements at the Close of the Mesozoic. Duration of the Mesozoic.

LiFe OF THE Mesozoic. : : é 2 : : 5 : : . + 52r Comparison of the Life of the Paleozoic and the Mesozoic. Plan of Study. INVERTEBRATES . 523

Chalk. Sponges. Corals. Crinoids. Sea Urchins (Echinoids). Starfish. Brachiopods. Pelecypods. Gastropods. Cephalopods. Ammonites. Naked Cephalopods (Belemnites). Crustaceans. Insects.

FISHES AND AMPHIBIANS . : ¢ ; i P : A 3 : 2 a Gee

REPTILES. : ‘ : : : : Fi 2 3 : 5 : “ : + 536 Reptiles with Mammalian Characters.

DINOSAURS . A 539

Carnivorous Dinosaurs. Unarmored Quadrupedal Dinosaurs (Sauropoda). Unarmored Bipedal Herbivorous Dinosaurs (Unarmored Predentata). Armored Dinosaurs (Armored Predentata). Summary of Dinosaurs. Migration and Extinction of Dinosaurs. Size as a Factor in Extinction.

CROCODILES 5 ; 5 : a ‘ f = : C 5 3552

MaRINE REPTILES. : : . . B . a . 5 ; ‘ - <<." 552 Ichthyosaurus. Plesiosaurus. Mosasaurus (Sea Lizards). Turtles.

FLiyinc Reprites (PTERosAuRs) : d , ‘ - ‘ F : 4 5 - 558

ToOoTHED Birps . 3 < 2 7 ‘ : e F 5 A P és 5 = 560 Archzopteryx. Hesperornis. Ichthyornis.

PLANTS : . ‘ c 5 : A : é ; F 3 5 = : - 5065 Horsetails. Cycads. Ferns. Gymnosperms. Angiosperms.

CLIMATE . : : : 2 ? : : A F : : 6 ° 5 - 569 Triassic. Jurassic. Cretaceous.

Triassic. Cretaceous.

CHAPTER XXI CENOZOIC ERA: THE AGE OF MAMMALS. TERTIARY PERIOD

COMPARISON OF THE LIFE AT THE CLOSE OF THE MESOZOIC AND THE BEGINNING OF THE CENOZOIC Subdivisions of the Cesorsic Er

PuysicAL GEOGRAPHY OF THE TERTIARY . 5 ‘ Pn pee : . EoceNE : : ° “ ‘ : * yh , s ; Atlantic and Gulf Coe Pacific Coast. Western Interior. Eocene of Other Continents.

OLIGOCENE . : c 5 : ‘ 2 : : : . 3 Atlantic and Gulf Chae Western Interior. Pacific Coast. Oligocene of Other Continents.

MIOCENE . - x 7 : : “ e : F .

Atlantic and Gulf Coase Economic Products of the Miocene. Western Interior. Pacific Coast. Mountain Building. Basis for Separation

into Periods. Igneous Activity. Miocene of Other Continents.

PLIOCENE ; : : s : E : 5 5 ‘ 3 Atlantic at Gulf Coates: Western Interior. Pacific Coast. Pliocene Elevation. High Plains and Bad Lands. Pliocene of Other

Continents.

Life OF THE TERTIARY . A ; : : z . : i : “

Rise of Mammals. Archaic Mammals of Ancient Ancestry. Amblypoda.

Ancestors of the Carnivores. Marine Mammals. Zeuglodon. An-

cestors of Existing Whales. Ancestors of the Hoofed Mammals

(Ungulates). Divergence of the Even and Odd-toed Hoofed Mammals (Ungulates).

Factors IN THE EVOLUTION OF MAMMALS Mammalian Teeth. Feet. Limits to Evolanions

Opp-Torp MAMMALS (PERISSIDACTYLS) : ; : é : , ; F 6 Titanotheres. Rhinoceroses. Tapirs. Horses. Summary of the Evolution of the Horse. Probable Cause of the Evolution of the Horse. Cause of the Extinction of the Horse in North America. Elephants. Summary of the Evolution of the Elephant.

EvEN-TOED MAMMALS (ARTIODACTYLS)

Camels. Deer. Cattle, Sheep, and Casts, Seine and Relaced! ‘kate A Climbing Ungulate.

INSECTIVORES : : - . 2 . °

RODENTS (GNAWING Ae 5 : *

TRUE CARNIVORES . ; A 4 4 5 :

Primates (MONKEYS, APES, LEMURS) . : 2 4

Birds . - 5 x ; 5 ‘ : ‘ ; : : REPTILES AND AMPHIBIANS : a ; . 5 ‘

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574 574

59°

PAGE INVERTEBRATES . a 5 ; : 5 f - 5 : 5 * . 3 - 626 Insects. Horseflies, Tsetse Flies, and Ants. VEGETATION ; . : ; i A P : 4 4 c ‘ : 5 7 630 Grasses. Dzmonhelix. Geological History of Sequoias. Diatoms. Exceptional Preservation of Plants. Plant Localities in North America. CLIMATE. ; ; ‘ P ; ‘ : ‘ : : ; : ‘ : See Difficulty in Determining Tertiary Climates. Eocene. Oligocene. Miocene. Pliocene.

Errects oF ISOLATION AND MIGRATION . ; , : ; : ; : c - 636 Eocene Invasion. Oligocene Invasion. Miocene African Invasion. Pliocene South American Invasion and Intermigration between the Old and New Worlds. Duration of the Tertiary.

CHAPTER XXII : QUATERNARY CHANGES AT THE CLOSE OF THE TERTIARY . ‘ ‘ ‘ : - ‘ . - 643 Elevation. Glaciation. Changes in Life.

DISTRIBUTION OF THE Icke SHEETS . F 7 . ° 5 . ‘ F ‘. - 645 Other Continents. North America.

DEVELOPMENT OF THE ICE SHEETS . 5 ‘ é ‘ - - : - - OAT Thickness of Ice Sheets at Center.

GLACIAL AND INTERGLACIAL STAGES . 3 ‘ 3 : . 5 : : 5 - 648 Characteristics of Former Drift Sheets.

History OF THE GREAT LAKES : 651

Preglacial Drainage. Origin of ae Basins. Great Lakes Sisven ate Champlain Subsidence.

OTHER PLEISTOCENE LAKES . s é . A : : ; 3 - ; a sORO Lake Agassiz. Lake Bascom. Great Basin Lakes.

CausES OF GLACIATION , 4 : : ' : : A 5 - A : . 660 Elevation. Astronomical. Atmospheric Hypothesis.

EFFECTS OF GLACIATION . : : : : : ; ; A : Fi . 662

LIFE OF THE PLEISTOCENE ; 663

Interglacial Deposits. North and South Migrations during Glacial and Interglacial Times. Deposits beyond the Ice Sheets or Protected from Them. Deposits on the Last Drift. Vegetation. Mammoths and Mastodons. Edentates. Pleistocene Carnivores. Horses, Camels, etc. Birds.

PREHISTORIC MAN, 2 F ‘ : Pe, A ‘ : % : k oy OFA Eolithic. Paleolithic Man. Neolithic Man. Man in North America. Birthplace of Man. Effect of the Advent of Man. Fourure HABITABILITY OF THE EARTH 3 5 A . s ‘. ms 5 : = 093

APPENDIX ComMON MINERALS . - E ‘ ° : C - F ' ° , : - 685

INTRODUCTION

Geotocy is the science that treats of the earth and its inhabitants as revealed in the rocks, and therefore deals with its constitution and structure, with the operation of the forces which led to its present condition, and with the occurrence and evolution of its life. In the search for this knowledge it calls to its aid astronomy, chemistry, physics, and biology. Geology is, in fact, a composite science, making use of the physical sciences in unrolling the complicated history and structure of this planet.

Because of the breadth of its scope, geology has been divided into a number of branches which are, however, in such a large measure interdependent, that a general knowledge of all is often essential to a thorough understanding of any one.

Astronomic or Cosmic Geology. — Since the earth is one of the planets of the solar system, all theories of its origin must at the same time consider the origin of the other planets, and vice versa. Consequently, astronomy and geology are dependent upon one another in all attempts at determining the genesis of the earth.