OF THE LEVEL OF THE SEA. 69 



as tertiary ?"* It appears to me that Mr Lyell has solved 

 the difficulty} by classing amongst the tertiary formations 

 " all those geological monuments which cannot be proved 

 to have originated since the earth was inhabited by man." 

 The appearance of man on the surface of the earth is an 

 event of such transcendent importance, as to justify its be- 

 ing used as the separating line of the recent or human pe- 

 riod, and those which preceded it. Changes of level have 

 occurred in every stage of the Earth's history : those of 

 which I have bggn treating must have taken place during 

 that which immediately preceded the recent period, and, of 

 course, the organic remains belong to that division of the 

 tertiary group, which he has named the newer pliocene. 

 It is of great importance that every circumstance connected 

 with this deposit should be carefully observed and recorded, 

 as an accurate knoAdedge of it cannot fail to throw much 

 light on that hitherto obscure branch of geology, the na- 

 ture and origin of the different alluvial beds which compose 

 the earthy covering of the more ancient formations ; and, 

 as it must be the object of the science to proceed from what 

 is known to what is unknown, we cannot too minutely in- 

 vestigate that part of it which forms the first step in the 

 descending series, in order that we may obtain firmer foot- 

 ing in prosecuting our researches into the more remote 

 epochs of the history of the Earth. 



* Treatise on Geology, p. 263. 



