Correspondence. 197 
tinuovis the outlet of the lakes through Chicago would eventually be re- 
stored and that at Niagara dried up, that in 1000 years water would be- 
gin at times to flow over this ridge and would be continuous in 1500 
years, that in 2000 years the stream would equal Niagara, that in 2500 
years Niagara would intermit, and in 3000 years would cease altogether. 
Prof. Chamberlain resumed the considei'ation of loess and in substance 
agreed with previous speakers in the opinion that it was not due to aqu- 
eous or to Eeolian origin entirely but that both had been concerned in 
the work. It graduated he said in some places into glacial clay and 
passed Vjelow into coarse sand becoming finer also as it recedes from the 
edge of the ice sheet and from the border of the rivers. The great ele- 
vation which it reached — 1000 feet above sea level in some cases — ex- 
cludes water as the sole depositing agent. The suggestion was accord- 
ingly made that much of the material had been blown up the gentle 
glacio-fluvial slopes and deyjosited upon the higher levels. This of course 
implies a dry time. The demarkation of the loess due to the two agen- 
cies is difficult, perhaps impossible, but one of the chief efforts of geolo- 
gists \vorking in the region should be to discover marks of differentia- 
tion between the deposits and so learn how to distinguish them. 
Prof. Albert Penck of Vienna, being called upon by the chairman, re- 
sponded with a brief account of the loess in its typical region, the Euro- 
pean Alps. He would approve the view of its double origin and said 
that the same conclusion had been reached in Europe. He regarded 
the loess as peculiar to the northern portion and said that it did not oc- 
cur on the south side of the Alps, where he also added there was evi- 
dence of recent depreFsion which was lackirg on the north. 
The section concluded its meeting on Thursday afternoon, leaving Fri- 
day free for various short excursions to local points of interest. On Sat- 
urday a general excursion to the St. Clair flats was announced and that 
arrangements had been made for those members of the Association who 
desired to do so to attend the meeting of the British Association at To- 
ronto, V)eginningon the 18th of August. 
The unsolved and' interminable problem of Niagara was taken up by 
Prof. F. R. Taylor who attempted what may be called a correlation of 
the views of geologists regarding this gorge and the retreat of the ice. 
After sketching rapidly the circumstances attending the formation of the 
Niagara river he called attention to the difference in width of the chasm 
at different places and explained it by the theory that it was due to the 
varying quanity of water going down the river. In the earliest stage 
the water of the whole system of the four lakes united passed over the 
fails. Then for a time an outlet was opened by the Nipissing valley in- 
to the Ottawa and only the water of lake Erie such as it then was came 
in this direction. Later by an uplift of the land this outlet was closed 
and the whole drainage again sent over Niagara. During the former 
of these intervals Mr. Taylor thinks that the narrow channel between 
the cantalever bridge and the whirlpool, except the lower 400 yard?, was 
excavated and the wider portions above and below these i)oints by the 
greater river of earlier and later time. Mr. Taylor also briefly referred 
