xii TABLE OF CONTENTS 



CHAPTER PASS 



151. Subsurface Water or Ground Water . . .315 



152. Geysers; How Caused ; Yellowstone Park . .319 



153. Run-off; Drainage 322 



154. Pools and Lakes ; Swamps 322 



155. The Work of Running Water ; Water Erosion . 325 



156. Divides; Passes 328 



157. Falls and Rapids ; Rock Layers .... 329 



158. River Development ; Young and Old Rivers ; Grad- 



ing ; Flood Plain ; Meanders ; Cycle of Erosion 332 



159. Rivers in Dry Climates ; Floods . . . .341 



160. Accidents in River Development; Beheading; In- 



trenched Meanders ; Engrafted and Dismem- 

 bered Rivers ....... 342 



161. Alluvial Cones and Fans 349 



162. Deltas . . . 350 



163. History and Rivers; Early Settlements; Commerce 353 



1 64. Great Rivers of the United States .... 354 



XI. ICE AND -WiND SCULPTURES. 



165. Snow in Winter ; Snow Crystals . ... . 363 



166. Glaciers; Crevasses; Moraines; Striae . . . 363 



167. Greenland and the Antarctic Ice Fields . . .371 



1 68. Icebergs ; Proportion under Water . . . 372 



1 69. Glacial Formations ; Drumlins ; Eskers ; Erratics . 375 

 170. Glaciated Areas . . . .^. . . . 379 



171. Glacial Lakes ' . . . *. . . .380 



172. Waterfalls Due to Glaciation 382 



1 73. Glacial Period 382 



1 74. Effect of the Glacial Period upon Plants and Animals 384 



1 75. Man and the Glacial Period .*.... 385 



176. Wind Work . . 386 



177. Wind Erosion 386 



1 78. Wind Burying and Exhuming .... 387 



1 79. Sand Dunes . 387 



XII. Low AREAS OF THE EARTH. 



1 80. Level Areas ; Plains ; Plateaus . . . . 39 1 



181. Coastal Plains ; Belted Plains .... 392 



182. Industries on Coastal Plains ; The Fall Line . .. 396 



183. Embayed Plains ; Reentrant Bays . . . .399 



184. Lake Plains 400 



185. River Plains; Bottom Lands . ' . . . .401 



1 86. Prairies of the United States . 402 



