GORGES AT MINNEHAHA FALLS 41 



gorge of Minnehaha creek above the junction, that below the junction, ' 

 and the abandoned branch. The abandoned branch and that below the 

 junction Grant interpreted as the work of a former arm of the Missis- 

 sippi river, while the part of the Minnehaha gorge above the junction is 

 exclusively the work of that creek. To a certain degree that interpreta- 

 tion is correct. 



Minnehaha creek flows some 20 feet wide al:)Ove and below the falls. 

 At the falls it spreads out over a short rapids, and then plunges 60 feet 

 into the gorge of its own making. The stream descends more than 40 

 feet from the base of the fall to its mouth. For 600 feet from the fall it 

 flows in the part of the gorge which it alone has eroded. This Upper 

 Minnehaha gorge is about 200 feet wide. At its head it forms nearly a 

 semicircle, with the falls at its deepest part. The fall is thus apparently 

 in a gorge much greater than its own width, though in fact the bottom of 

 the gorge is only wide enough for the fall and the stream. The height 

 of the falls is nearly the full depth of the gorge at its head, and fully half 

 this depth is in the easily eroded Saint Peter sandstone. Deeper erosion 

 is prevented mainly by the blocks of limestone which have fallen on the 

 sides and bottom of the gorge and over which the stream rushes in its 

 rapid descent from the foot of the fall. From the Upper gorge the 

 stream enters what may be termed here the Lower Minnehaha gorge, 

 through which it descends gradually to the Mississippi river. 



The Upper and Lower gorges are alike in respect to narrowness at the 

 bottom and rapid descent, and since the Upper gorge is crooked, its junc- 

 tion at nearly right angles with the Lower gorge is not an exceptional 

 feature. The sole reason for distinguishing the Lower Minnehaha gorge 

 from the Upper is because there is a third part which extends continuous 

 in direction, width, and depth with the former. This branch of the gorge 

 is now fenced as a deer park and may be designated the Deer Park gorge. 

 It extends with slowly decreasing depth for about 1,000 feet from Minne- 

 haha creek and ends blindly. Grant interpreted this and also a distinct 

 channel which runs from above the end of the gorge to the Mississippi as 

 the course of an ancient arm of the river, which they must be. The chan- 

 nel is flat bottomed, cut quite down to the limestone ledge, and is 300 to 

 400 feet -wide, with an escarpment 10 to 15 feet high on cither side. The 

 left scarp runs from its north end, on the brink of the present gorge of 

 the Mississippi, around in a curve back to tbe same near the mouth of 

 Minnehaha creek. The right scarp coincides with the right wall of the 

 Deer Park and Lower gorges. 



That there was an island in the Mississippi dividing a main east arm 

 from the longer west arm before Saint Anthony falls had receded to the 



