40 F. W. SARDESON SAINT ANTHONY FALLS 



Southward from the mouth of Soldier gorge, there are other block- 

 covered terraces skirting the limestone scarp for half a mile, which 

 formed in part the sites of falls and in part the walls of consequent 

 gorges alongside of falls. The Mississippi river at that early stage 

 swept over the limestone bench west as well as east of the present railway 

 track above the limestone scarp. The terraces here are all intercepted by 

 the sandstone scarp which bounds the foot of the main gorge at no great 

 distance from the limestone scarp, and they are crossed by three creeks, 

 which have made deep ravines, so that their evidence is obscured. Their 

 surface appears to have been covered by fewer and smaller limestone 

 blocks than the more northern terraces were, and the Saint Peter sand- 

 stone, being thus less protected, has suffered more from siibsequent ero- 

 sion. The last terrace toward the south is notably little protected by 

 limestone blocks. It is high, however, a few feet only from, the top of 

 the sandstone. The near-by limestone scarp on the north lacks the upper 

 limestone bed. There appears to have been at this point a rapids or fall 

 of 20 to 25 feet only, though the bed of the channel was 30 to 35 feet 

 below where the top of the limestone would be if the limestone formation 

 was entire here as it is elsewhere. 



Briefly stated, the evidence shows us that the Saint Anthony falls at 

 this early stage was as low as possible — that is, measuring from the top 

 of the limestone which formed the crest, the falls were 35 to 40 feet to the 

 bed of the river. The limestone is nearly 35 feet thick, so that the foot 

 of the falls nearly coincides with the top of the Saint Peter sandstone. 

 This sandstone was excavated 5 to 20 feet, this depth being filled again 

 by blocks of limestone and debris. The descent from the foot of the fall 

 in Soldier gorge is gradual, while that of the east fall is at first more 

 rapid. From the evidence altogether, I estimate that the bed of the 

 Mississippi at a distance from the fall, as at Fort Snelling, was 60 feet 

 below the top of the limestone ledge at this stage. From this ledge now 

 to the river is about 100 feet, and to the rock bottom of the gorge at Fort 

 Snelling 175 feet, as shown in plate 2, figure 1. 



The Gorges at Minnehaha Falls 



The Minnehaha gorge begins at the mouth of the creek, on the right 

 side of the Mississippi rivei-, al)out half a mile above Soldier gorge, just 

 described, and two miles above Fort Snelling. It extends for half a 

 mile (see map, plate 1), and then, as U. S. Grant has made known, it 

 branches, each branch extending about one-eighth of a mile to an abrupt 

 head. The gorge as a whole may be distinguished into three parts — the 



