138 NARRATIVE OF THE EXPEDITION. 



tributaries which it receives in this distance, are, on the right, the 

 St. Peter's, Upper and Lower Iowa, Turkey River, Desmoines, and 

 Salt Rivers ; and, on the left, the St. Croix, Chippewa, "Wisconsin, 

 Rock River, and the Illinois. One hundred miles below St. An- 

 thony, it expands for a distance of twenty-four miles into the sylvan 

 sheet of Lake Pepin, at the foot of which it receives the large 

 volume of the Chippewa River, which originates on the sandy 

 tracts at the sources of the Wisconsin, Montreal, and Ontonagon ; 

 and it is from this point that its continually widening channel 

 exhibits those innumerable and changing sand-bars, which so 

 embarrass the navigation. But in all this distance, it is only at 

 the Desmoines and Rock River rapids that any permanent serious 

 impediment is found in its navigation, with the larger craft. 



The fourth change in the physical aspect of this river, is at the 

 junction of the Missouri, and this is an almost total and complete 

 one; for this river brings down such a vast and turbid flood of 

 commingled earths and floating matter, that it characterizes this 

 stream to its entrance into the Gulf of Mexico. If its length of 

 channel, velocity, and other leading phenomena had been accu- 

 rately known at an early day, it should also have carried its name 

 from this point to the ocean. Down to this point, the Mississippi, 

 at its summer phases, carries the character of a comparatively 

 clear stream. But the Missouri, which, from its great length and 

 remote latitude, has a summer freshet, flows in with a flood so 

 turbid and opaque, that it immediately communicates its quali- 

 ties and hue to the milder Mississippi. At certain seasons, the 

 struggle between the clear and turbid waters of the two streams 

 can be seen, at opposite sides of the river, at the distance of 

 twenty or thirty miles. Entire trees, sometimes ninety feet long, 

 with their giant arms, are swept down the current; and it is not 

 unusual, at its highest flood, to observe large, spongy masses of a 

 species of pseudo pumice carried into its channel, from some of its 

 higher western tributaries. 



To such a moving, overpowering liquid mass, there are still, 

 below the Missouri, rocky banks, and occasionally isolated cliffs, 

 to stand up and resist its sweep ; but its alluvions become wider 

 and deeper opposite to these rocky barriers. Its bends stretch 

 over greater distances, and its channel grows deeper at every ac- 

 cession of a tributary. The chief of these, after passing the 



