G. K. Warren— Valley of the Minnesota and Mississippi. 421 
Niagara in volume, and would have been sufficient to prevent 
the formation of such excessive accumulation of débris in its 
course, such as the Mississippi is now making below the Min- 
nesota River, although it is probable that the material brought 
| into it from the near proximity of the Falls of St. Anthony 
7 would have had the usual effect of somewhat increasing the 
slope and shoalness just below its junction, and decreasing the 
j Mississippi above the Falls of St. Anthony, probably equaled 
Be d . 
thus moved by feebler currents. The resu ting material is 
% 
