QUESTIONS 521 



solid matter heated to such a temperature, pressure should 

 be withdrawn, or if the normal heat should be increased, 

 the heated matter might become molten and find its way 

 to the surface. What causes uprising and outpouring of 

 molten material is a question that is at present unanswer- 

 able. We know only that this does occur, and has resulted 

 in such volcanoes as Monte Nuovo, Mount Pelee, Vesuvius, 

 and other less famous volcanoes all over the world. Geysers 

 are spouting hot springs that are found in regions of recent 

 volcanic activity. Earthquakes are shocks communicated 

 to the surface of the earth from breaks or slips in rock 

 structure of the earth's crust. 



Mountains are the great regions for the mining of metals. 

 It is supposed that the heat generated by the folding and 

 crushing of the earth's crust in these regions has brought 

 about the accumulation of the metal in cracks or crevices 

 called veins. Bituminous coal is a sedimentary rock of 

 vegetable origin, which has been deposited under such 

 conditions that the carbon instead of being oxidized was 

 preserved. 



QUESTIONS 



What is the probable condition of the earth's interior? 



Describe the eruption and present condition of Monte Nouvo. 



What has been the history of Vesuvius? 



What is Mount Pelee' s story? 



Describe a geyser. 



What causes earthquakes? 



How has coal been formed? 



