Pleistocene Papers at the Madison Meetings. 175 
isolated discovery, for American caves, unlike those of Great 
Britain and Europe, are almost or wholly destitute of traces 
of their habitation by early man. 
Prof. Chamberlin regards the greater part, or perhaps all, 
of the evidence for Glacial man in America as untrustworthy. 
Onl} T very rare implements or artificially flaked fragments of 
stone have been found at considerable depths in glacial 
deposits, and these may be best explained by their falling 
through the hollows left by tree roots, which go down to reach 
permanent moisture ten or twenty feet below the surface. 
Instead of deserving to be called implements, most of the 
flaked stones found at Trenton, N. J., and elsewhere in the 
river gravels, are to be classed, according to Mr. Holmes' re- 
searches, as "quarry rejects.'" The conditions attending the 
deposition of these gravels in the Glacial period would be 
unfavorable for man's abode and loss of implements in his 
rude hunting and fishing; but during comparatively recent 
times these gravels have been worked and flaked for the man- 
ufacture of implements which were used and lost throughout 
the adjoining country. 
Prof. E. W. Cxaypole compared the attitude of many Amer- 
ican scientists concerning this question with the reluctance 
of European geologists to accept the discoveries of early man 
in the Somme valley. Men now live close to the borders of 
glaciers and ice-sheets. In Europe the Neolithic stage of cul- 
ture, or partial use of polished stone implements, was reached 
before the ice of the Glacial period was melted away. 
Mr. Upham spoke of evidences of man's existence on the 
shores of the glacial lakes Iroquois and Agassiz, as published 
by Gilbert and Tyrrell. The gravel and sand beaches of lake 
Agassiz enclose no boulders which would be brought by float- 
ing ice, and their absence indicates a mild climate during 
tin- recession of the ice-sheet. If the accumulation of the ice 
was caused by a high uplift of the land and its departure was 
due to a depression, the climatic conditions attending the 
close of the Glacial period may have been nearly as temperate 
along the boundary of the retreating ice as they now are on 
the same latitude. In Alaska an abundant boreal temperate 
flora, including forest trees, grows on the margin of the wan- 
ing Malaspina ice-sheet. 
