CONTENTS. 



INTRODUCTORY. 



PAGE 



Definition of Geology, and its Departments ....'. 1-2 



Geology, 1 ; Principal Departments, 2 ; Order of Treatment, 2. 



PART L 



DYNAMICAL GEOLOGY, 



CHAPTER I. 



Atmospheric Agencies . . . , . . , . , „ 3-8 

 Soils, 4 ; General Explanation, 6 ; Granite, Gneiss, Volcanic Rocks, etc., 7 ; Lime- 

 stone, 7 ; Sandstones, 7 ; Slate, 7. Mechanical Agencies op the Atmosphere. 

 —Frost, 8 ; Winds, 8. 



CHAPTER II. 

 Aqueous Agencies .......... 9-82 



Section 1. Risers, 9. Erosion of Rain and Rivers, 9 ; Hydrographical Basin, 10; 

 Rate of Erosion of Continents, 10 ; Law of Variation of Erosive Power, 11. Ex- 

 amples of Great Erosion now going on : Waterfalls, 12 ; Niagara, General Descrip- 

 tion, 12 ; Recession of the Falls, 12 ; Other Falls, 13 ; Time necessary to excavate 

 Niagara Gorge, 14; Ravines, Gorges, Canons, 15 ; Time, 17. Transportation and 

 Distribution of Sediments, 18; Experiments, 18; Law of Variation, 19: 1. Re- 

 lation of Velocity to Erosion and Sedimentation, 21 ; illustrated by Colorado and 

 Platte Rivers, 21. 2. Rivers seek their Base- Level, 21 ; Rivers as Indicators of 

 Crust-Movements, 22. 3. Stratification, 22. 4. Winding Course of Rivers, 23. 

 5. Flood-Plain Deposits, 24 ; River-Swamp, 24 ; Natural Levees, 25 ; Artificial 

 Levees, 25 6. Deltas, 26 ; Process of Formation, 28 ; Rate of Growth, 29 ; 

 Age of River-Deposits, 30. 7. Estuaries, 31 ; Mode of Formation, 31 ; Deposits 

 in Estuaries, 32. 8. Bars, 32 ; Improvement of Bars, 33. 



Section 2. Ocean. — Waves and Tides. — Waves, 34 ; Tides, 35 ; Examples of the 

 Action of Waves and Tides, 35 ; Transporting Power, 38 ; Deposits, 39 ; Oceanic 

 Currents, 39; Theory of Oceanic Currents, 39; Application, 41; Geological 

 Agency of Oceanic Currents, 42 ; Submarine Banks, 43 ; Land formed by Ocean 

 Agencies, 44. 



Section 3. Ice, 45. Glaciers. — Definition, 45 ; Necessary Conditions, 46 ; Rami- 



