ILLUSTRATIONS IN THE TEXT XXV 



FIO. PAGE 



134. The central cone of Vesuvius as it appeared after the eruption of 1906 132 



135. A sunken road upon Vesuvius filled with indrifted ash . . . 133 



136. View of Vesuvius from the southwest during the waning stages of 



the eruption 133 



137. The main lava stream advancing upon Boscotrecase .... 133 



138. A pine snapped off by the lava and carried forward upon its surface . 133 



139. Lava front pushing over and running around a wall in its path . . 134 



140. One of the ruined villas in Boscotrecase 134 



141. Three diagrams to illustrate the sequence of events during the cone- 



building and crater-producing periods 135 



142. The spine of Pel rising above the chimney of the volcano after the 



eruption of 1902 136 



143. Successive outlines of the Pele" spine 137 



144. Corrugated surface of the Vesuvian cone due to the mud flows which 



followed the eruption of 1906 138 



145. View of the Kammerbiihl near Eger in Bohemia .... 139 



146. Volcanic plug exposed by natural dissection of a volcanic cone in 



Colorado 140 



147. A dike cutting beds of tuff in a partly dissected volcano of south- 



western Colorado 140 



148. Map and general view of St. Paul's rocks, a volcanic cone dissected 



by waves ........... 141 



149. Dissection by explosion of Little Bandai-san in 1888 .... 141 



150. The half-submerged volcano of Krakatoa before and after the erup- 



tion of 1883 142 



151. The cicatrice of the Banat 142 



152. Diagram to illustrate a probable cause of formation of lava reservoirs 



and the connection with volcanoes upon the surface . . . 143 



153. Effect of relief of load upon rocks by arching of a competent forma- 



tion 144 



154. Character profiles connected with volcanoes 146 



155. Diagrams to show the effect of decomposition in producing spheroidal 



bowlders . .... . . . . . . . 150 



156. Spheroidal weathering of an igneous rock ...... 151 



157. Dome structure in granite mass . . . . . . . .152 



158. Talus slope beneath a cliff . .153 



159. Striped ground from soil flow . 154 



160. Pavement of horizontal surface due to soil flow 154 



161. Tree roots prying rock apart on fissure .... . . . 154 



162. Bowlder split by a growing tree .... . . . . . 155 



163. Rock mantle beneath soil and vegetable mat ...... 155 



164. Diagram to show the varying thickness of mantle rock upon the 



different portions of a hill surface . ,* .. . .156 



165. Gullies from earliest stage of a river's life . . . . . . 160 



166. Partially dissected upland 160 



167. Longitudinal sections of upper portion of a river valley . . 161 



