Geology, Vol. 1 [of 3]

CHAPTER I.. Preliminary Outline.

PRELIMINARY OUTLINE.

Subdivisions, 1. Dominant processes, 2.

PAGE

+Astronomic Geology+ 2 The earth as a planet, 2. Its satellite, 3. Dependence on the sun, 4. Meteorites, 4.

+Geognosy+ 5 I. The Atmosphere 5

Mass and extent, 6. Geologic activity, 6. A thermal blanket, 7. II. The Hydrosphere 7 Oceanic dimensions, 8. Geologic activity, 8. Chief horizons of activity, 9. III. The Lithosphere 9

Irregularities, 10. Epicontinental seas, 11. Diversities of surface, 12. The surface mantle of the lithosphere, 12. The crust of the lithosphere, 13. The interior, 14. Varieties of rock in crust, 14. Stratified rocks, 14. Conformability, 15. Relative ages, 15. The crystalline rocks, 16. Four great sedimentary eras, 17. The Archean complex, 18.

+General Table of Geologic Divisions+ 19

CHAPTER II.. The Atmosphere As a Geological Agent.

THE ATMOSPHERE AS A GEOLOGICAL AGENT.

+The Atmosphere as a Direct Agency+ 21 I. Mechanical Work 21 Transportation and deposition of dust, 22. Transportation and deposition of sand, 25. Formation of dunes, 26. Shapes of dunes, 26. The topographic map, 30. Topography of dune areas, 32. Migration of dunes, 33. Distribution of dunes, 35. Wind ripples, 37. Abrasion by the wind, 38. Effects of wind on plants, 40. Indirect effects of the wind, 41. II. Chemical Work 41 Precipitation from solution, 41. Oxidation, 42. Carbonation, 43. Other chemical changes, 43. Conditions favorable for chemical changes, 43.

+The Atmosphere as a Conditioning Agency+ 43 I. Temperature Effects 44 II. Evaporation and Precipitation 50 III. Effects of Electricity. 52

+Summary+ 54

CHAPTER III.. The Work of Running Water.

THE WORK OF RUNNING WATER.

+Rain and River Erosion+ 57 Subaërial Erosion without Valleys 58 The Development of Valleys 63 By the growth of gullies, 63. Limits of growth, 67. The permanent stream, 70. Other modes of valley development, 73. Structural valleys, 77. The courses of valleys, 77. The development of tributaries, 78.

+A Cycle of Erosion. Its Stages+ 80

+General Characteristics of Topography Developed by River Erosion+ 92

+Special Features Resulting from Special Conditions of Erosion+ 92 Bad-land topography, 93. Special forms of valleys; canyons, 94.

+The Struggle for Existence Among Valleys and Streams+ 100 Piracy, 103.

+Rate of Degradation+ 105 Material in solution in river water, 107.

+Economic Considerations+ 108

+Analysis of Erosion+ 110 Weathering. 110 Transportation 115 Transporting power and velocity, 115. How sediment is carried, 116. Corrasion 119 Abrasion, 119. Solution, 122.

+Conditions Affecting the Rate of Erosion+ 123 The Influence of Declivity 123 The Influence of Rock 124 Physical constitution, 124. Chemical composition, 124. Structure, 125. The Influence of Climate 127

+Effects of Unequal Hardness+ 132 Rapids and falls, 132. Rock terraces, 140. Narrows, 141. Other effects on topography, 142. Adjustment of streams to rock structures, 146.

+Influence of Joints and Folds+ 150 Joints, 150. Folds, 154.

+Effect of Changes of Level+ 161 Rise, 161. Sinking, 170. Differential movement, warping, 171.

+The Aggradational Work of Running Water+ 177 Principles involved, 177. The Deposits 181 Types, 181. Alluvial fans and cones, 181. Ill-defined alluvium, 183. Alluvial plains, 184. Flood-plains due to alluviation, 186. Flood-plains due to obstructions, 188. Levees, 188. Flood-plain meanders, cut-and-fill, 190. Scour-and-fill, 194. Materials of the flood-plain, 196. Topography of the flood-plain, 196. Topographic adjustment of tributaries, 197. River-lakes, 198. Deltas, 198. Delta lakes, 204.

+Stream Terraces+ 204 Due to inequalities of hardness, 204. Normal flood-plain terraces, 205. Flood-plain terraces due to other causes, 208. Discontinuity of terraces, 209. Termini of terraces, 210.

CHAPTER IV.. The Work of Ground (underground) Water.

THE WORK OF GROUND (UNDERGROUND) WATER.

Conditions influencing descent of rain-water, 213. Supply of ground-water not altogether dependent on local rainfall, 215. Ground-water surface—water table, 215. Depth to which ground-water sinks, 216. Movement of ground-water, 220. Amount of ground-water, 221. Fate of ground-water, 221.

+The Work of Ground-water+ 222 Chemical Work 222 Quantitative importance of solution, 223. Deposition of mineral matter from solution, 225. Mechanical Work 226

+Results of the Work of Ground-water+ 226 Weathering, 226. Caverns, 227. Creep, slumps, and landslides, 231. Summary 232

+Springs and Flowing Wells+ 234 Mineral matter in solution, 235. Geysers, 236. Artesian wells, 242.

CHAPTER V.. The Work of Snow and Ice.

THE WORK OF SNOW AND ICE.

+Snow- and Ice-fields+ 244 The passage of snow into névé and ice, 246. Structure of the ice, 247. Texture, 247. Inauguration of movement, 248.

+Types of Glaciers+ 251

+The General Phenomena of Glaciers+ 256 Dimensions, 256. Limits, 258. Movement, 259. Conditions affecting rate of movement, 261. Likenesses and unlikenesses of glaciers and rivers, 262.

+Surface Features+ 266 Topography, 266. Surface moraines, 266. Relief due to surface débris, 268. Dust-wells, 269. Débris below the surface, 272.

+Temperature, Waste, and Drainage+ 273 The winter wave, 274. The summer wave, 276. The temperature of the bottom, 276. Temperature of the interior of the ice, 277. Compression and friction as causes of heat, 278. Summary, 279. Movement under low temperature, 279. Evaporation, 279. Drainage, 280.

+The Work of Glaciers+ 281 Erosion and Transportation 281 Getting load, 282. Conditions influencing rate of erosion, 283. Summary, 286. Varied nature of glacial débris, 286. The topographic effects of glacial erosion, 287. Fiords, 290. The positions in which débris is carried, 290. Transfers of load, 292. Wear of drift in transit, 298. Deposition of the Drift 298 Beneath the body of the ice, 298. At ends and edges of glaciers, 299.

+Types of Moraines+ 301

The terminal moraine, 301. The ground moraine, 301. The lateral moraines, 302. Distinctive nature of glacial deposits, 304. Glaciated rock surfaces, 304.

+Glacio-Fluvial Work+ 305

+Icebergs+ 307

+The Intimate Structure and the Movement of Glaciers+ 308 The growth and constitution of a glacier, 308. The arrangement of the crystal axes, 312. The Probable Fundamental Element in Glacial Motion 313 Melting and freezing, 313. Accumulated motion in the terminal part of a glacier, 316. Auxiliary Elements 317 Shearing, 317. High temperature and water, 318. Applications, 319. Corroborative Phenomena 320 Other Views of Glacier Motion 321

CHAPTER VI.. The Work of the Ocean.

THE WORK OF THE OCEAN.

Volume and composition, 324. Topography of bed, 326. Distribution of marine life, 328.

+Processes in Operation in the Sea+ 329 Diastrophism, 329. Vulcanism, 332. Gradation, 333.

+Movements of the Sea-water+ 334 Differences in density and their results, 335. Differences in level and their results. 335. Movements generated by winds, 336. Movements generated by attraction, 322. Aperiodic movements, 338. Summary, 339.

+Waves+ 339 Wave-motion, 339.

+Work of the Waves+ 342 Erosion 342 By waves and undertow, 342. Topographic Features Developed by Wave Erosion 349 The sea-cliff, 349. Chimney rocks, etc., 350. Sea caves, 350. The wave-cut terrace, 351. Wave erosion and horizontal configuration, 353. Transportation by Waves 354 Deposition by Waves, Undertow, and Shore Currents 355 The beach, 355. The barrier, 356. The spit, the bar, and the loop, 357. Wave-built terraces, 363. Effect of Shore Deposition on Coastal Configuration 363

+Summary of Coastal Irregularities+ 364

+The Work of Ocean-currents+ 366

+Deposits of the Ocean-bed+ 368 Shallow-water Deposits 369 Littoral deposits, 369. Non-littoral, mechanical deposits in shallow water, 369. Characteristics of shallow-water deposits, 373. Topography of shallow-water deposits, 374. Chemical and organic deposits, 375. Limestone, 378. Deep-sea Deposits 378 Contrasted with shallow-water deposits, 378. Sources, 380. Mechanical inorganic deposits, 380. Organic constituents of pelagic deposits, 382. Chemical deposits, 383.

+Lakes+ 386

Changes taking place in lakes, 387. Lacustrine deposits, 388. Extinct lakes, 388. Lake ice, 389. Saline lakes, 391. Indirect effects of lakes, 392. Composition of lake waters, 392.

CHAPTER VII.. The Origin and Descent of Rocks.

THE ORIGIN AND DESCENT OF ROCKS.

+Composition of Igneous Rocks+ 395 Leading elements, 396. Union of elements, 397. Formation of minerals, 397. Sources of complexity, 398. The leading minerals of igneous rocks, 399. The feldspathic minerals, 400. The ferromagnesian minerals, 400. Summary of salient facts, 401.

+The Nature of Molten Magmas+ 401 Time required in crystallization, 402. Successive stages of crystallization, 403.

+The Fragmental Products of Sudden Cooling+ 404 Pyroclastic rocks, 404.

+The Glassy Rocks+ 406 The solid glasses. 406. The first stages of crystallization, 407. The obsidians, 407.

+Special Structures+ 410 Flow structure, 410. Amygdaloids, 411.

+The Porphyritic Rocks+ 411

+The Phanerocrystalline Rocks+ 412 The phanerites, 412. The granites, 413. The syenites, 415. The diorites, 416. The gabbros, 416. The peridotites, 416. The basalts, 417. The dolerites, 417. General names, 418.

+Derivation of Secondary Rocks+ 420 Regolith, 422. Disrupted products: arkose and wacke, 422. Disintegrated products, 422. Classes of Sedimentary Rocks 422 Shales, sandstones, and conglomerates, 422. Limestones and dolomites, 424. Precipitates, 424. Iron-ore beds, 425. Silicious deposits, 425. Organic rocks, 426.

+Internal Alterations of Rocks+ 426 Oxidation and deoxidation, 427. Solution and deposition, 427. Hydration and dehydration, 428. Carbonation and decarbonation, 429. Molecular rearrangements, 431. The Salient Features of Rock Descent 431

+The Reascensional Process+ 432 Induration under ordinary pressures and temperatures, 432. Cavity filling, 436. Fissure filling; veins, 437. Solution as well as deposition, 437. Concretions, 438. Replacements and pseudomorphs, 439. Incipient crystallization, 439.

+Reconstruction under Exceptional Conditions+ 440 Slaty structure, 441. Foliation, schistosity, 443. Metamorphism by heat, 446. Metamorphism by heat and lateral pressure, 448. Deep-seated metamorphism, 449. Completion of the rock cycle, 449.

+Various Classifications and Nomenclatures+ 449 New System of Classification and Nomenclature 451 The Proposed Field System 451 The phanerites, 451. The aphanites, 452.

+The Proposed Quantitative System+ 454

+Reference List of the More Common Minerals+ 460

+Reference List of the More Common Rocks+ 467

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