X CONTENTS. 



PAGE 



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 land- 

 slides, 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. 



Snow- and Ice-fields 244 



The passage of snow into neve 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. Con- 

 ditions affecting rate of movement, 261. Likenesses and un- 

 likenesses of glaciers and rivers, 262. 



Surface Features 266 



Topography, 266. Surface moraines, 266. Relief due to 

 surface debris, 268. Dust-wells, 269. Debris 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 



