EXTINCT ANIMALS 



tons of solid salts of lime in solution is 

 carried every year past that spot. Now a 

 cubic block of limestone measuring a yard in 

 each dimension weighs about two tons. Accord- 

 ingly, 250 thousand solid cubic yards of 

 rock are carried past Kingston every year 

 by this little river ! Enough to build a new 

 St. Paul's Cathedral every year ! Think, then, 

 what must be the enormous quantities of solid 

 matter dissolved and carried away by such 

 rivers as the Mississippi and the Amazon. And 

 remember that in addition to this dissolved lime- 

 stone there is almost as large a bulk of fine sand 

 and mud carried along by most rivers ! What 

 becomes of it ? It is deposited in layers, and 

 forms what we call stratified rock. You see it, 

 some of it, on the seashore when the tide goes 

 back, in the form of layers of sand, but most of 

 it is deposited far out in the deep bottom of the 

 sea — the lime being taken out of solution by 

 shell-making plants and animals. But where the 

 land is rising, the sand or ground which is ex- 

 posed when the tide goes back, would after a few 

 years have been raised away from the sea and 

 become hard rock. Layer after layer is imposed 

 and raised from the sea bottom. Without 



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