17B The American Geologist, September, 1898 
Prof. F. W. Putnam directed attention to the occurrence of 
both argillite and jasper implements on the surface about 
Trenton, N. J., while the only flaked stones found there in the 
glacial gravels arc argillite. The working of the jasper quar- 
ries, as shown by Mercer and Volk, belongs to a postglacial 
and comparatively late epoch. If the specimens obtained in 
the gravel deposits were introduced by tree roots, burrows, and 
Tailing talus slopes, there could be no discrimination selecting 
the argillite. He had examined the freshly undermined bluffs 
of a stream at Trenton and discovered a flaked stone of un- 
questionably artificial origin beneath a large boulder where 
no root or burrow could account for it. During his long ex- 
perience in the excavation of aboriginal earthworks, he has 
observed no holes due to decaying roots at greater depths than 
two or three feet below the surface. Although trees send 
roots much deeper, their slow decay is attended with the sift- 
ing of fine sand or clay into the place of the root so as to fill 
it as fast as the decay takes place. Numerous well authenti- 
cated discoveries of stone implements and even human bones 
in formations of glacial origin seem to afford adequate and 
convincing proof of man's presence here in the Ice age. 
After this discussion Section E resumed its separate sessions, 
in which the following Pleistocene papers were presented : 
Sonic questions respecting glacial phenomena about Madison. 
By Prof. T. C. Chambebmn, Chicago, 111. Madison, Wis., the 
city of this meeting, was described as situated within the area 
of the later drift near the end of the Green Bay lobe of the 
continental ice-sheet. The direction of glaciation at Madison 
was southwestward, with which the longer axes of the drum- 
lins are parallel. About 2,500 drumlins have been mapped, 
mostly by Mr. Buell, in southeastern Wisconsin, and probably 
as many more remain to be mapped throughout the eastern 
part of the state. The sand and gravel cores of the Madison 
drumlins appear to have been subglacial deposits: and the 
overlying till, enclosing more and larger boulders than the till 
of the surrounding lowlands, seems to have been englacial, 
excepting perhaps that a large part of its loam, according to 
the hypothesis of Salisbury in a subsequent paper, may have 
been brought by winds. The osars, kames, and moraines of 
the region were also briefly noticed. 
