TABLE OF CONTENTS 



CHAPTER I ^ 



PAGES 



Some General Considerations . . . . . . 1-12 



Composition of the soil, 1 — Factors for plant growth, 

 2 — Plant food elements, 3 — Abundance of plant food 

 elements, 4 — Soil-forming rocks, 5 — Soil-forming min- 

 erals, 6 — Relative abundance of minerals, 7 — Organic 

 matter, 8 — The soil and the plant, 9. 



V 

 CHAPTER II 



Soil-forming Processes * 13-30 



Water, 10 — Wind, 11 — Ice, 12 — Heat and cold, 13 



— Frost, 14 — Plants and animals, 15 — Oxidation and 

 carbonation, 16 — Deoxidation, 17 — Hydration, 18 — 

 Solution, 19 — A general statement of weathering, 20 — 

 Factors affecting weathering, 21 — Law of mineral and 

 rock decay, 22 — Special cases of weathering, 23 — Prac- 

 tical relationships of weathering, 24. 



CHAPTER III 

 The Geological Classification of Soils . . . 31-45 



Residual soils, 25 — Distribution of residual soils, 26 



— Cumulose soils, 27 — Colluvial soils, 28 — Alluvial 

 soils, 29 — Distribution of alluvial soils, 30 — Marine 

 soils, 31 — Characteristics of marine soils, 32 — Distri- 

 bution of marine soils, 33. 



CHAPTER IV 



Geological Classification of Soils {Continued) . . 46-64 

 The ice sheet, 34 — The American ice sheet, 35 — 

 Cause of the ice age, 36 — The extension of the ice sheet, 

 37 — The ice as a soil builder, 38 — Glacial till soils, 39 



