A HISTORY OF SCIENCE 



Hutton looks about him for a clew, and soon he finds 

 it. Everywhere about us there are outcropping rocks 

 that are not stratified, but which give evidence to the 

 observant eye of having once been in a molten state. 

 Different minerals are mixed together; pebbles are 

 scattered through masses of rock like plums in a pud- 

 ding; irregular crevices in otherwise solid masses of 

 rock so-called veinings are seen to be filled with 

 equally solid granite of a different variety, which can 

 have gotten there in no conceivable way, so Hutton 

 thinks, but by running in while molten, as liquid metal 

 is run into the moulds of the founder. Even the 

 stratified rocks, though they seemingly have not been 

 melted, give evidence in some instances of having been 

 subjected to the action of heat. Marble, for example, 

 is clearly nothing but calcined limestone. 



With such evidence before him, Hutton is at no loss 

 to complete his hypothesis. The agency which has 

 solidified the ocean-beds, he says, is subterranean heat. 

 The same agency, acting excessively, has produced 

 volcanic cataclysms, upheaving ocean -beds to form 

 continents. The rugged and uneven surfaces of moun- 

 tains, the tilted and broken character of stratified rocks 

 everywhere, are the standing witnesses of these gigantic 

 upheavals. 



And with this the imagined cycle is complete. The 

 continents, worn away and carried to the sea by the 

 action of the elements, have been made over into rocks 

 again in the ocean-beds, and then raised once more 

 into continents. And this massive cycle, in Hutton' s 

 scheme, is supposed to have occurred not once only, 

 but over and over again, times without number. In 



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