VALLEY OF THE MISSISSIPPI. 17 



The existence of this fact did not fail to excite the 

 avidity of adventurers, who were, however, disap* 

 pointed in the pretended quantity and locality of this 

 native metal. But although there is every reason to 

 consider the masses of this metal, as Avell as others 

 which were shown to me during this route by a chief 

 of the Monomonies, collected near the outlet of the 

 river St. Croix of the Mississippi, as entirely adven- 

 titious in their relation to the surrounding strata, still 

 even these insulated facts justify us in supposing 

 them as strongly indicative of the approaching termi- 

 nation of the secondary formation in this direction. 

 We cannot yet indulge our inquiries to any advan- 

 tage any further to the northward, as none of the 

 other travellers in this quarter have favoured us with 

 the smallest ray of geological information. Still we 

 are led to suppose that the Falls of St. Anthony,* 

 no less than the numerous portages and rapids 

 of the Utowa river are occasioned by some con- 

 siderable deviation in the strata from that almost 

 horizontal position which they otherwise present. 

 This opinion, however, as it regards the Mississippi, 

 amounts to nothing more than conjecture, for, as in 

 the beds of many other rivers, there is no possibility 

 of deriving any information regarding the nature of 

 its sources from the debris or gravel deposited along 

 its banks, knowing, as we do, the wide extent of 



* According to the observations communicated to me by 

 Major Long, testaceous lime-stone exists both above and below 

 these falls. 



c 



