The mechanics of crater explosions—Grander volcanic eruptions of cinder cones—The eruption of Volcano in 1888—The eruption of Taal volcano on January 30, 1911—The materials and the structure of cinder cones—The profile lines of cinder cones—The composite cone—The caldera of composite cones—The eruption of Vesuvius in 1906—The sequence of events within the chimney—The spine of Pelé—The aftermath of mud flows—The dissection of volcanoes—The formation of lava reservoirs—Character profiles—Reading references 115 CHAPTER XI THE ATTACK OF THE WEATHER The two contrasted processes of weathering—The rôle of the percolating water—Mechanical results of decomposition: spheroidal weathering—Exfoliation or scaling—Dome structure in granite masses—The prying work of frost—Talus—Soil flow in the continued presence of thaw water—The splitting wedges of roots and trees—The rock mantle and its shield in the mat of vegetation—Reading references 149 CHAPTER XII THE LIFE HISTORIES OF RIVERS The intricate pattern of river etchings—The motive power of rivers—Old land and new land—The earlier aspects of rivers—The meshes of the river network—The upper and lower reaches of a river contrasted—The balance between degradation and aggradation—The accordance of tributary valleys—The grading of the flood plain—The cycles of stream meanders—The cut-off of the meander—Meander scars—River terraces—The delta of the river—The levee—The sections of delta deposits 158 CHAPTER XIII EARTH FEATURES SHAPED BY RUNNING WATER The newly incised upland and its sharp salients—The stage of adolescence—The maturely dissected upland—The Hogarthian line of beauty—The final product of river sculpture: the peneplain—The river cross sections of successive stages—The entrenchment of meanders with renewed uplift—The valley of the rejuvenated river—The arrest of stream erosion by the more resistant rocks—The capture of one river by another—Water and wind gaps—Character profiles—Reading references 169 CHAPTER XIV THE TRAVELS OF THE UNDERGROUND WATER The descent within the unsaturated zone—The trunk channels of descending water—The caverns of limestones—Swallow holes and limestone sinks—The sinter deposits—The growth of stalactites—Formation of stalagmites—The Karst and its features—A desert from the destruction of forests—The ponore and the polje—The return of the water to the surface—Artesian wells—Hot springs and geysers—The deposition of siliceous sinter by plant growth—Reading references 180 CHAPTER XV SUN AND WIND IN THE LANDS OF INFREQUENT RAINS