428 



FIRST YEAR SCIENCE 



1755, sweeping away thousands of people who had rushed 

 into an open part of the city to get away from the falling 

 buildings caused by the earthquake shock. 



Sometimes earthquakes are followed by terrible fires 

 which cannot be extinguished on account of the disarrange- 

 ment of the water supply. This was the case in the San 

 Francisco earthquake. 



203. Products of Mountain Regions. When rocks are 

 folded and crushed, in forming mountains, heat is gener- 

 ated, and heated water 

 under pressure acts upon 

 the components of the 

 rocks and dissolves some 

 of their minerals, which 

 accumulate in cracks 

 and crevices called veins. 

 When the overlying 

 beds have been worn 



away, 



these mineral 



DEEP DOWN IN THE CALUMET AND 



HECLA MINE. 

 The world's greatest copper mine. 



Nevada Mountains 

 In one are found 



and in the 

 great quantities 



veins, formed deep be- 

 low the surface, are ex- 

 posed and can be mined. 

 Mountains are therefore 

 the great mining re- 

 gions. 



In this country min- 

 ing is a most important 

 industry in the Sierra 



Appalachian region. 



of copper, silver 



and gold, and in the other iron and coal. In the old 

 Laurentian Mountain region, near the Great Lakes, much 

 copper is found. The Alps and the Pyrenees are among 

 those mountains that have few minerals. 



