598 | Vestiges of Glacial Man in Minnesota. [June, 
the bleached appearance proved a merely temporary characteris- 
tic, for although the quartzes received a thorough washing up 
immediately after being collected, they directly began to take on 
anew a tawny yellowish tint which, within a few months, became 
decidedly pronounced. They were again carefully cleansed with 
brush and water, again to resume their rusty tone of color. Ina 
few instances the process of brushing clean was repeated at inter- 
vals of four or five months, a third and even a fourth time, with 
similar results. The degree of discoloration appears to vary with 
the quality of the specimens affected, the most compact varieties 
of mineral undergoing the least modification of tint. The color- 
ing also fluctuates, probably, with the fluctuating proportion of 
iron in the containing soil. 
It was soon ascertained that the notch, and the surfaces imme 
diately surrounding it, afford no boulders nor other supplies of 
quartz except these chips. Nor does quartz appear on the east 
shore within a radius of perhaps an eighth of a mile from the 
spot, although it occurs plentifully just north and south of these 
limits, both in the form of veins in the slate rock of the region, | 
and in that of waterworn river-wash and occasional boulders j 
Waterworn lumps of quartz are now and then found, it is Beg i 
the subjacent till, but the latter lies several feet lower than 
quartz-bearing stratum, beneath which it directly peon 
hence could never have yielded the specified objects thr ahon 
ural processes. An additional fact, worthy of note, is the im 
ably small size of the pieces disclosed. But a single f the 
: here at 
larger than a club-head has, as yet, come to light anyw iv 
notch, and that one was not imbedded in the undis dE. 
at the notch proper, but in the débris at its base and W ad 
Even could there have existed at this site masses of mee ne 
portant enough to furnish the tens of thousands of i sh . 
lumps with which the place has proved to be pa thus : 
wholly incredible that such rocky masses could have C The 
absolutely annihilated, except through human iner a 
waterworn stone rubbish below the quartzes pene | 
grated, therefore so we should expect the latter likewise : 
There is no known reason why, having been subject 
influences, the one should have been broken into sm escaped di- : 
even splintered into the tiniest bits, while the other Se 
integrating forces. 
is.) Se orale AA eT A 
to the same 
