Early Man in Minnesota. — Holmes. 231 
channel down through these deposits, reaching finally its present 
bed in the Huronian slates upon which the gravels were laid 
down. When the river flowed actively along the east side of the 
channel, w^ashing the base of this bluff, the latter was no doubt 
much steeper than now and had a hight of about twenty-five 
feet. The horizontal glacial deposits were exposed to their full 
thickness, and in all probability, relying upon observations made 
in the vicinit}-. the underlying quartz-bearing slates at the base 
were uncovered to the depth of from five to ten feet. When 
the river ceased to erode actively at this point, the loosely bedded 
gravels and sands forming the upper part of the blufl? dis- 
integrated and descended to the base, covering the slates and 
the exposed edges of the formations and gradually producing 
the practically stal^le slope seen to-day. 
The primitive inhabitants of the valley sought quartz where- 
ever the veins were conveniently exposed. Finding at this point 
a natural descent to the river b}- a gully, now the old roadwa}', 
they were able to reach the exposures of quartz, and naturally 
established their shops on the nearest available spots. It is prob- 
able that the wide flood plain now under water was in those 
earlier daj^s swept b}' strong freshet currents exposing the quartz- 
bearing formations over large areas, thus furnishing unusual op- 
portunities to the quartz- working natives. These are preciseh' 
the conditions that prevailed in the river channel in front of the 
old village site at the dam, as shown b}' a photogi'aph of the 
place made before the dam was built. Even if exposures of quartz 
were not found at the lower end of the '■ notch '" they certainl}' 
did occur in the river banks a few hundred feet away, since at 
the present time, with a rise of ten feet in the water level, the 
quartz-bearing rocks are still exposed in the opposite bank of the 
river. Professor Winchell is of the opinion that in early times 
this spot was probably the only convenient or available landing 
place near the head of the rapids, since the banks elsewhere were 
either steep or swampy; and it is not improbable that quartz, 
obtained about the head of the rapids or even at the mouth of Elk 
river above, where veins occur, was brought to this spot in canoes 
and broken up and trimmed prior to further transportation. That 
the source of the quartz, or part of it, was really near at hand is at- 
tested by the presence of masses and fragments of considerable size 
on this site, and it seems highly probable that when these work- 
