340 THE CAUSES OF THE 



XI 



our record entirely consists of accumulations of 

 mud, superimposed one on the other ; seeing in 

 the next place that any particular spots on which 

 accumulations have occurred, have been constantly 

 moving up and down, and sometimes out of the 

 reach of a deposit, and at other times its own 

 deposit broken up and carried away, it follows that 

 our record must be in the highest degree imper 

 fect, and we have hardly a trace left of thick 

 deposits, or any definite knowledge of the area 

 that they occupied, in a great many cases. And 

 mark this ! That supposing even that the whole 

 surface of the earth had been accessible to the 

 geologist, that man had had access to every part 

 of the earth, and had made sections of the whole, 

 and put them all together, even then his record 

 must of necessity be imperfect. 



But to how much has man really access ? If 

 you will look at this map you will see that it 

 represents the proportion of the sea to the earth : 

 this coloured part indicates all the dry land, and 

 this other portion is the water. You will notice 

 at once that the water covers three-fifths of the 

 whole surface of the globe, and has covered it in 

 the same manner ever since man has kept any 

 record of his own observations, to say nothing of 

 the minute period during which he has cultivated 

 geological inquiry. So that three-fifths of the 

 surface of the earth is shut out from us because 

 it is under the sea. Let us look at the other 



