126 FeatherstonhaugWs Geological Report. 



the nature of this report to enlarge it with repeated relations of 

 the great heauty and amenity of the scenery of the upper por- 

 tion of this often-described river ; the formation being the same 

 along the whole line, the geologist has to limit his observations 

 to incidents connected with geological causes, and reserve what 

 belongs to descriptive geography, and the manners and customs 

 of the Indian nations he passes amongst, as I shall do upon this 

 occasion, to a work of appropriate character. It is one of the 

 great advantages of geological science, that where interesting 

 minerals and metals and fossils are wanting, there is always in- 

 struction to be received in the study of the causes which have 

 modified the surface of the earth in whatever direction we 

 move. This is particularly true as it regards the bed of the 

 Mississippi and the surrounding country, the physical geogra- 

 phy of which is remarkable. The valley through which the 

 stream flows is generally, below Lake Pepin, from one and a 

 half to two miles wide. There has at some time been a contin- 

 uous alluvial deposite through its entire breadth, and over which 

 the water has flowed in a stream, as it does now in the Lower 

 Mississippi, uninterrupted by islands. Since the reduction of 

 the general water-level, the river, often divided into more 

 than one channel, now cuts its way through the ancient depos- 

 ite, sometimes the main channel being on one side, sometimes 

 on another, and separating the old bottom into innumerable 

 islands, some of them, at times, being several miles long, and 

 all of them having a level of from six to twelve feet above the 

 streams. This state of things makes the navigation difficult to 

 strangers, who, believing themselves in the channel, get into 

 bays from which there is no egress. Whenever the current 

 slackens there is always reason to doubt the channel. These 

 islands are extremly well wooded, and afford generally excel- 

 lent situations to " camp out" at night, as it is called, the soil 

 being dry, the situation sheltered, and dry wood abundant. 

 The banks of the valley ( for they can scarcely be called the 

 banks of the river, since where the stream runs close to one 



