CONTENTS 



INTRODUCTION 



PAGE 



Astronomic or Cosmic Geology. Structural Geology. Dynamical Geology. 

 Industrial Geology. Historical Geology. Length of Geological Time. 

 Present Status of Geology. Fundamental Terms. Rocks. Sedimentary 

 Rocks. Igneous Rocks. Metamorphic Rocks. Divisional Planes . . 21 



PART I. PHYSICAL GEOLOGY 



CHAPTER I 

 WEATHERING 



Mechanical Agencies . .27 



Frost. Talus. Rock Glaciers. Creep of Soils. Changes in Daily 

 Temperature. Mechanical Action of Animals and Plants. Rain. 

 Wind. Lightning. 



Chemical Agencies ~ " 35 



Solution. Oxidation. Hydration. Carbonation. Organisms. Compari- 

 son of Effects of Chemical and Mechanical Weathering. 



Results of Weathering 38 



Spheroidal Weathering. Differential Weathering. Widening of Valleys. 

 Rock Mantle and Soil. Kinds of Soil. Removal of Soil. 



CHAPTER H 

 WORK OF THE WIND 



Wind and Sand 44 



Wind without Sand. Wind with Sand. Sand Dunes. Shape and Origin of 

 Dunes. Migration of Sand Dunes. Beneficial Effect of Dunes. Ma- 

 terial of Dunes. Height of Dunes. Eolian Sandstone. Dust. Loess. 



CHAPTER HI 



THE WORK OF GROUND WATER 



Work of Ground Water ............ 56 



Quantity of Ground Water. 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 62 



Origin of Springs. Constant and Intermittent Springs. Mineral Matter 

 in Spring Water. Mineral Springs. Temperature of Springs. Ther- 

 mal Springs. Geysers. 



7 



