TIME AND CHANGE 



transmutations they have undergone! They have 

 passed through Nature's laboratory and taken on 

 new forms and characteristics. 



"All sediments deposited in the sea," says my 

 geology, "undergo more or less chemical change," 

 and many chemical changes involve notable changes 

 in volume of the mineral matter concerned. It has 

 been estimated that the conversion of granite rock 

 into soil increases its volume eighty-eight per cent, 

 largely as the result of hydration, or the taking up of 

 water in the chemical union. The processes of oxid- 

 ation and carbonation are also expansive processes. 

 Whether any of this gain in volume is lost in the pro- 

 cess of sedimentation and reconsolidation, I do not 

 know. Probably all the elements that water takes 

 from the rocks by solution, it returns to them when 

 the disintegrated parts, in the form of sediment in the 

 sea, is again converted into strata. It is in this cycle 

 of rock disintegration and rock re-formation that 

 the processes of life go on. Without the decay of the 

 rock there could be no life on the land. Water and 

 air are always the go-betweens of the organic and 

 inorganic. After the rains have depleted the rocks 

 of their soluble parts and carried them to the sea, 

 they come back and aid vegetable life to unlock and 

 appropriate other soluble parts, and thus build up 

 the vegetable and, indirectly, the animal world. 



That the growth of the continents owes much to 

 the denudation of the sea-bottom, brought about by 



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