Volume Three

P. F. COLLIER & SON COMPANY NEW YORK

Copyright 1922 By P. F. Collier & Son Company

MANUFACTURED IN U. S. A.

GEOLOGY

The Science of the Earth's Crust

WILLIAM J. MILLER Professor of Geology, Smith College

P. F. COLLIER & SON COMPANY NEW YORK

PREFACE

In the preparation of this book the author has attempted to present, in popular form, the salient points of a general survey of the whole great science of geology, the science which deals with the history of the earth and its inhabitants as revealed in the rocks.

The use of technical and unusual terms has been reduced to a minimum compatible with a reasonable understanding of the subject by the layman. Each of the relatively few scientific terms is explained where first used in the text, and a glossary of common geological terms has been appended.

The matter of illustrations has received very careful attention, and only pictures, maps, and diagrams are used which actually illustrate important features of the text. A special point has been made to introduce only cuts of simple construction comparatively free from technicalities. Nearly every illustration is accompanied by a really explanatory title.

A number of the pictures are from the author's collection of photographs, and many of the line-cuts have either been made or considerably modified by the author. Among the numerous sources of illustrations, special mention should be made of the United States Geological Survey, the New York State Museum, the American Museum of Natural History, the University of Chicago Press, and various individuals, full credit being given wherever due.

William J. Miller.

Northampton, Mass.

CONTENTS

CHAPTER PAGE

I. Introduction 9

II. Weathering and Erosion 22

III. Stream Work 30

IV. The Sea and Its Work 51

V. Glaciers and Their Work 59

VI. The Action of Wind 71

VII. Instability of the Earth's Crust 76

VIII. Volcanoes and Igneous Rocks 99

IX. Waters Within the Earth 113

X. How Mountains Come and Go 130

XI. A Study of Lakes 142

XII. How the Earth May Have Originated 158

XIII. Very Ancient Earth History 164

XIV. Ancient Earth History 179

XV. Medieval Earth History 208

XVI. Modern Earth History 221

XVII. Evolution of Plants 249

XVIII. Geological History of Animals (Excluding Vertebrates) 259

XIX. Geological History of Vertebrate Animals (Including Man) 281

XX. Mineralogy 307

XXI. Economic Geology 342

Glossary of Common Geological Terms 377

LIST OF ILLUSTRATIONS

Ledge of Rock with Nearly Vertical Strata Frontispiece

PLATE FACING PAGE

1 Granite Weathering to Soil Leaving Residual Cores of Joint Blocks (Upper picture) 32

Looking-Glass Rock, Utah. Stratified Sandstone Sculptured by Wind Erosion (Lower picture) 32

2 Grand Canyon of the Yellowstone River. A Channel Worn by Erosion 33

3 Gorge of the Niagara River Below the Falls. A Sample of Recent Erosion 64

4 Winding Stream in the St. Lawrence Valley with Flood Plain (Upper picture) 65

Davidson Glacier, Alaska, Showing Action on the Valley's Walls and Floor (Lower picture) 65

5 Swift Current Valley in Glacier National Park, Formed by Stream and Glacier Action 96

6 Yosemite Valley from Western Entrance. The Result of Glacial Action 97

7 An Upbend Fold or Anticline in Maryland 128

8 Ledge of Igneous Rock Showing Joints (Upper picture) 129

Fault Fracture in Limestone Formations (Lower pictures) 129

9 Molten Lava Flowing Over a Cliff in Hawaii (Upper picture) 160

Dikes of Granite Cutting Old Rock (Lower picture) 160

10 Lassen Peak, California, in Eruption (Left picture) 161

Devil's Tower, Wyoming, Once a Mass of Molten Rock Forced Through Strata (Right picture) 161

11 Mammoth Hot Springs Terrace in Yellowstone National Park (Upper picture) 224

Crater Lake, Oregon, Formed by the Subsidence of a Volcano (Lower picture) 224

12 Archeozoic Rock, Oldest Known Rock Formation on Earth (Upper picture) 225

Twisted Mass of Stratified Limestone, Surrounded by Granite (Lower picture) 225

13 Paleozoic Rock, Covered with Oldest Known Animal Remains 256

14 "Stone-Lily" Stems in Ordovician Strata (Upper left picture) 257

Various Brachiopods in Ordovician Strata (Upper right picture) 257

Stratified Limestone of Middle Ordovician Era Containing Fossils (Lower picture) 257

15 A Landscape of the Coal Age (Upper picture) 288

Fossil Fern on a Piece of Shale (Lower picture) 288

16 Restoration of Huge Animals of the Mesozoic Era 289

17 Skeleton of Two-Legged Carnivorous Dinosaur (Large picture) 320

Earliest Known Bird Form (Insert) 320

18 Skeleton of Large Flying Reptile (Upper picture) 321

Skeleton of a Swimming Reptile of the Mesozoic Era (Lower picture) 321

19 Appalachians Along New River, Peneplain Upraised Again 352

20 Glacial Bowlder Left by Ice Sheet (Upper picture) 353

Esker, Deposited by a Stream in the Great Glacier (Lower picture) 353