2 FIRESIDE SCIENCE. 



another, and they all rest upon the great mass of 

 igneous rock which forms the mighty framework of 

 the earth's crust. Now it is apparent that if the 

 various strata of the sedimentary rocks had never 

 been disturbed, but had remained in their original 

 level position just as they were formed, rivers, 

 lakes, and springs could have had no existence. 

 There would have been no hills or mountains or 

 valleys, and the waters upon the earth must have 

 rested in vast holes or excavations upon its surface. 

 The rain would have managed to escape by soak- 

 ing into the porous strata, and remaining there un- 

 til, in part, driven off by evaporation from internal 

 or solar heat. It could not have formed definite 

 channels or rivers, as it does now, on the slopes 

 found upon every continent. The porous strata or 

 coatings, consisting of the mould, sand, and gravel, 

 would have received the rain, as has been said, and 

 a part of it would undoubtedly have been removed 

 by the agency of heat ; but a large portion would 

 . have penetrated downward, until it met with strata 

 wholly impervious, and there it would remain until 

 it acquired sufficient pressure to be forced out in all 

 directions into cavities constituting the seas. What 

 an oozy, damp condition of things must have existed 

 during the carboniferous and oolitic epochs, or be- 

 fore the great rock upheavals occurred ! 



Let us look for a moment at another point of no 







