Coal How Formed Charcoal. 149 



Clay. 

 Iron Ore. 



Lime Stone. 



Interior or Sectional View in the Coal Regions. 



remains and impressions of such have been 

 found in them. It is also probable that the 

 water on the earth, the heat inside of the 

 earth, volcanic action, and several successive 

 elevations and depressions of the surface had a 

 good deal to do with the formation of coal. 



1 7. Charcoal is made by covering, almost en- 

 tirely, a large pile of wood with sod and earth 

 and setting it on fire. 



