AND FRESH-WATER FORMATIONS. 315 



those they as properly belong as the present sands of 

 our sea shores. In all else, it is a mere question of 

 time. 



The last chapter has also excluded a whole division 

 of deposits, which had equally been confounded, 

 sometimes with the last, but more generally with 

 those which I am about to rank by themselves as pro- 

 perly deserving a separate place here. The differences 

 are important, if the causes of both have sometimes 

 been the same ; for these are deposits formed in the 

 present ocean, a portion of its bottom under a for- 

 cible change of place. They were those preparations 

 for future strata which are still forming under the 

 sea : and we may say that the time of their elevation 

 has been anticipated. 



Excluding then both these, there remain those 

 which I shall now attempt to distinguish and explain : 

 but though I must include them all in this chapter, 

 it will be seen that they demand separate classes, as 

 they are essentially different, under two leading heads ; 

 while, under other views, they may even demand a 

 further subdivision. If, for want of sufficient facts, I 

 cannot at present venture to divide them, future geo- 

 logists may fill up, by examples, this proposed divi- 

 sion ; as they will hereafter, I hope, find no diffi- 

 culty in furnishing the facts of which I am yet in 

 want. The basis of arrangement is supplied in this 

 theory. 



If Lake Superior were now to be suddenly drained, 

 we should find a series of strata covering its bottom ; 

 and from what we know of drained lakes, we should 

 discover, at least, sandstones, shales, and limestones, 

 together with loose clay, sand, marl, lignites, and 

 terrestrial organic fossils, both vegetable and animal. 

 Or, if it were to be filled up, through the deposits of 



