42 THE AGE OF THE EARTH 



say ; some geologists imagine it to have obliterated the 

 whole or greater part of the North Atlantic Ocean. For 

 my part I am content with a somewhat large island. 

 What area of this island, we may ask, would suffice to 

 supply the Cambrian sediments of Wales and Shropshire? 



FIG 3. Chart of the distribution of land and sea, and of the thickness of 

 deposits of the Cambrian system. The dotted lines indicate distances 

 of 100 and 20 miles from the shore. 



Admitting that the area of denudation was ten times as 

 large as the area of deposition, its dimensions are in- 

 dicated by the figure a b c d on the chart. This evidently 

 leaves room enough on the island to furnish all the other 

 deposits which are distributed along the western shores 

 of the Cambrian Sea, while those on the east are amply 



