CONTENTS xiii 



PART III 

 TRE WEATEEBING OF E0CK8 



PAGE 



I. Statement of General Problem; Principles involved in 



Rock-weathering 150 



Weathering defined 151 



1. Action of the Atmosphere 154 



(1) Nitrogen, Nitric Acid, and Ammonia of 



the Atmosphere 154 



(2) Carbonic Acid of the Atmosphere . . 156 



(3) Oxygen of the Atmosphere . . . 158 



(4) Effects of Heat and Cold . . .158 



(5) Effects of Wind 163 



2. Chemical Action of Water 165 



(1) Oxidation 165 



(2) Deoxidation 166 



(3) Hydration 166 



(4) Solution 168 



3. Mechanical Action of Water and of lee . . . 175 



4. Action of Plants and Animals. . • . . 180 



II. Consideration of Special Cases 185 



'1) Weathering of Granite 185 



'2) Weathering of Nepheline (Elasolite) Syenite . . 196 



[3) Weathering of Phonolite 197 



'4) Weathering of Diabase 198 



'5) Weathering of Basalt 205 



6) Weathering of Biorite 207 



7) Weathering of Andesite 207 



8) Weathering of Ultra Basic Rocks .... 208 

 ^9) Weathering of Sedimentary Eocks .... 212 



(10) Bemme: Importance of Hydration ; Loss of Constitu- 

 ents; Relative Durability of Various Minerals; Dis- 

 cussion of Processes involved in Feldspathic De- 

 composition ........ 220 



