Archaological Notes on Mumcsota. — Hershcy. 291 
press what I conceive to be the most probable explanation of 
the phenomena displayed. 
When implements or other artificially fracttired rock- 
masses are fotmd on the sloping sides of ravines or the banks 
of streams which flow through sandy plains, as in central Min- 
nesota, it is safe to say that they constitute not the least evi- 
dence of the occurrence of similar forms in the undisturbed 
strata, except in the extreme upper portion. The formation 
of a perpendicular bank in the loosely compacted sand and 
fine gravel of the Alinnesota Glacial flood-plain deposits is prac- 
tically an impossibility. Just above the old mill on the west 
side of the Little Falls and St. Cloud road, the Swan river is 
now engaged in cutting a cove into the 27-foot bank of modi- 
fied drift. The excavation is so fresh that vegetation has not 
secured a foothold on the slope. Undisturbed strata outcrop 
at ihe top of the section, but below the edges of the layers in 
place are hidden by an extensive talus of coarse sand and fine 
gravel. This section is significrnt as showing that even during 
a period of active erosion a talus will obscure the edges of the 
strata. As the talus is removed by the action of the stream 
at the base, it is being constantly renewed by the breaking 
down of the strata above. 
At the "notch," in view of Miss Babbitt's explicit state- 
ment that the implements occurred in a definite stratum which 
outcropped at the foot of the bank on each side and the upper 
end of the ravine, we cannot refer them to ordinary talus trans- 
portation from the upper stratum of the plain. It is probable 
that soon ^after the main excavation of the ravine, and before 
its sides had fallen down very much, it was the site of a land- 
ing-place and rough workshop of the aborigines. Here thev 
brought the quartz which they had quarried from the veins 
in the rapids, and fashioned it into the rough outlines of the 
implements which were finished at the village. In the course 
of time a great quantity of refuse had collected on the flat floor 
of the ravine, extending as a uniform sheet to the foot of the 
slo])ing walls. Duriiig the long time which has intervened 
between then and now, the loose gravel and sand have worked 
down the sides of the ravine until they reached a slope of 
comparative stability. In this way, a portion of a quartz- 
bearing stratum, perhaps a foot or more in width, came to be 
