36 



THE PAST CONDITION 



we have regarded as stationary, goes down, as it does 

 so, both A and B go further out from the shore, which 



Fig. 4. 



will be at y\ x 1 y\ being the new sea-level. The con- 

 sequence will be that the layer of mud (A), being now, 

 for the most part, further than the force of the current 

 is strong enough to convey even the finest debris, will, 

 of course, receive no more deposits, and having attained 

 a certain thickness will now grow no thicker. 



We should be misled in taking the thickness of that 

 layer, whenever it may be exposed to our view, as a 

 record of time in the manner in which we are now 

 regarding this subject, as it would give ns only an 

 imperfect and partial record it would seem to repre- 

 sent too short a period of time. 



Suppose, on the other hand, that the land (C D) 

 had gone on rising slowly and gradually — say an inch 

 or two inches in the conrse of a century, — what would 

 be the practical effect of that movement ? Why, that 

 the sediment A and B which has been already depos- 

 ited, would eventually be brought nearer to the shore- 

 level, and again subjected to the wear and tear of the 

 sea ; and directly the sea begins to act upon it, it would 

 of course soon cut up and carry it away, to a greater 

 or less extent, to be re-deposited further out. 



