PROCEEDINGS OF SCIENTIFIC SOCIETIES. 501 


he Mississippi, and hence the water of the Missouri river is several 
ed feet higher than that of the Mississippi, at points in the same 
widens out to from forty to sixty miles. Sometimes the river, 
at the “Grand Tower” and at ‘‘Le-montagne-qui-trempe 4-l’eau,” and 
several other places, is found flowing between bluffs not even a mile 
‘part; but the bluffs on one side or the other are always found to be a 
detached mass, and the main valley exists there too. 
Two remarkable exceptions to this occur at the rapids, —one at Keokuk, 
‘other at Rock Island. Without lengthening this paper to such an 
ve - the sediment brought by its tributaries, was gone. very- 
~ Mong its course these tributaries continued to deposit at their 
