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" It has long been a matter of common observation that 

 the rivers are cutting their channels through alluvial de- 

 posits of greater depth and extent than could have been 

 formed by the present streams." Every individual whose 

 attention has been at all directed to the subject, has ob- 

 ' served small streams where apparently larger ones must 

 have flowed at some former period ; from the great rivers 

 that drain whole continents, to the little streams that re- 

 ceive the drainage from the rains that fall upon the hills 

 and lowlands everywhere, proving that some gradual de- 

 crease in the amount of drainage has taken place without 

 any general disturbing physical causes, which would have 

 deranged and changed the ancient channels. 



The excess of evaporation over precipitation, of precipi- 

 tation over drainage, at all times since the earliest 

 emergence of land upon the globe, results from the fact 

 that part of the aqueous vapor develops vegetable and 

 animal organisms, being incorporated with the vital tissues 

 and so cannot all be precipitated again, and part of the 

 precipitation is also used in the same way, and thus the 

 drainage cannot get all the precipitation. Thus the 

 evaporating areas always receive less than they give, and 

 must constantly decrease. 



For ambient air is matter, and the seas 



Less dense than earth, yet surely matter too, 



Ever as land doth grow, so these decrease, 



Each type of life the earth doth hide from view — * 



Throughout the solid crust where delvers shew — 



Once in the waters or on land it grew. 



Fed by the liquid and the foodful air 



Ever in death earth's solid parts accrue 



The fauna growing purer and more fair 



Where richer floral growth the ancient rocks declare. 



And surely does not many a type below 

 Prove vaster, warmer waters, richer air ? 

 Beneath where now small forms tho' beautious grow, 

 Man finds the tropic monster in his lair; 



