REVIEWS 795 



covered at times of flood. It is of course probable that the crest of 

 the ledge has been worn down where the river flows over it, but such 

 erosive covering by the river does not fit in well with the view that 

 this same portion was the source whence large quantities of vein 

 quartz were quarried at the same time. It is clearly urging a bare 

 possibility at best rather than a probable occurrence. 



If, however, the case rested merely on the possibility of reaching 

 the source of the quartz while yet the uppermost layers of the original 

 plain were in the process of formation, it might be ungenerous to 

 refuse to entertain the utmost possibilities of the case in favor of 

 glacial man in America. But the facts of the case, taken just as given 

 in this paper, do not seem to the reviewer to afford even a plausible 

 ground for assigning the quartz chips to the glacial stage of the river. 

 The surface deposit in which they are found, as described and illus- 

 trated in the paper, not only does not bear the characteristics of a 

 glacio- fluvial deposit, but bears quite clear evidence that it is not 

 glacio-fluvial. The descriptions cite the fact that the surface deposit 

 is highest near the bank of the present bottoms, after the common 

 habit of existing degrading rivers. This habit is recognized and the 

 facts are summarized in the following quotation (p. 73): "At Little 

 Falls, Minn., the eastern portion of the sandy plain on the east side of 

 the Mississippi is several feet lower than the crest of the plain at the 

 east end of the dam. That fact is important. After the great 

 glacial river which overspread the entire plain at Little Falls had with- 

 drawn into the narrower limits of an eroded streambed, that river, 

 often in freshet from the effects of the melting ice-sheet, occasionally 

 re-overflowed the entire plain, disturbing and overturning the sandy 

 surface, mixing into its materials every chipped quartz blade or spall 

 which had been placed by the hand of man upon the surface adjoin- 

 ing the newly eroded and narrower channel. The higher altitudes of 

 the plain along the Mississippi between 'The Notch' and the dam 

 were caused by successive stages of recurring overflovvage, creating 

 additional surface deposits upon the plain nearest to the newly formed 

 river bank." This is indeed "important," as the author himself 

 naively remarks, since it shows, as the author also recognizes with 

 equal unconsciousness of its real meaning, that it is the characteristic 

 action of streams of the present non-glacial regime. It is here recog- 

 nized, with undoubted correctness, that the quartzes were buried "by 

 disturbing and overturning the sandy surface" and by "additional 

 surface deposits." The reference of this, however, to glacial waters is 



