336 QUESTIONS. 



110. State in full what is said of the leveling operations of water. 

 What is said of the agency of heat ? 



111. Of what benefit to the earth are volcanoes ? What is the dis- 

 tinction between extinct and active volcanoes ? How is it supposed 

 that an eruption is produced ? Describe the phenomena of an erup- 

 tion. 



112. When was the first eruption of Vesuvius that is on record? 

 What was its condition just before this ? State in full what is said 

 of the burial of Herculaneum and Pompeii. What happened to Ve- 

 suvius in 1822 ? What is the size of Etna ? What is said of its erup- 

 tion in 1669 ? 



113. What does Mantell say of one of Etna's eruptions? 



114. Describe the crater of Kilauea. Where is Tomboro? Give 

 Lyell's description of the effects of one of its eruptions. 



115. Give the facts in regard to Graham's Island, What is said 

 of other volcanic islands ? 



116. Give the statement about an island near Iceland. 



117. How may changes in the temperature of the earth's crust 

 cause earthquakes ? Give Prof. Dana's illustration. What is said of 

 the two vibrations produced by an earthquake ? State the effects of 

 earthquakes. 



118. What is said of solfataras ? What of hot springs? Describe 

 the geysers of Iceland. 



119. Explain their operation. 



120. State in full what is said of sand being moved by wind. 



121. What is said of gradual alterations of levels ? Give the state- 

 ment about the Temple of Jupiter Serapis. 



122. What does Hugh Miller say about the old coast-lines of Scot- 

 land ? State the evidences of a gradual change of level in Sweden 

 and Norway. 



1 23. What is said of organic agencies ? What of changes made by 

 man? 



CHAPTER XI. 



123. What is said of the succession of changes in the construction 

 of the earth's crust ? 



124. What is said of the development of life upon the earth ? Why 

 will what you have learned of present changes help you to understand 

 changes in the past? How does the geologist arrive at his conclu- 

 sions ? By what comparisons as to composition does he determine 

 the origin of rocks ? 



125. State the case of the shells found in rock. State the observa- 

 tion made about different roctas that contain shells. State the rea- 

 soning about the pudding-stone. 



