150 SPARKS FROM A GEOLOGIST'S HAMMER. 



over the farms and plantations, the hillsides and the 

 mountain gulches, to filch, as fast as they can, the fleeing 

 soil from the possession of the cultivator and owner. 



"The Father of Waters 



Seizes the hills in his hands, and drags them down to the ocean, 

 Deep in the sands to bury the scattered bones of the mammoth." 



Eoanyeline. 



Professor Croll estimates the lowering of the lands 

 through denudation to amount to one foot in 6,000 years. 

 The basin of the Ganges, however, has lowered one foot 

 in 2,300 years. On the contrary, Mr. Reade, a civil en- 

 gineer, estimates that England is lowered by denudation 

 only one foot in 13,000 years. He calculates that 500,- 

 000,000 of years must have elapsed since the first sedi- 

 mentary rocks were laid down in Europe, an estimate 

 evidently absurd, and throwing suspicion over his other 

 estimates, since Sir William Thompson has shown from 

 physical principles that 100,000,000 of years are all the 

 time allowable since the beginning of incrustation on the 

 earth. Similarly, Col. Forshey calculates that the Missis- 

 sippi river would fill the Gulf of Mexico in 1,000,000 of 

 years. 



All calculations are merely approximate. I am per- 

 suaded, however, that the conclusions of Croll and Reade 

 respecting the rate of denudation are quite below the 

 truth ; while, on the other hand, I suspect that the esti- 

 mated age of the Mississippi delta by Humphreys and 

 Abbott is quite too small, as I would hold that the opin- 

 ion of De Lanoye, who assigns 6,350 years as the age of 

 the Nile delta, is also too moderate in its allowance of 

 time. 



From this outline of the facts we perceive that conti- 



