1 82 * The American Geologist. September, i898 
gave a good summary of the aqueous argument. In 1881 
Chamberlain was almost alone in thinking that the loess of 
Iowa and Nebraska was partially aqueo-glacial and partially 
eolian, in which opinion others now concur. 
During the years 1878-1881 McGee discovered that the 
lowan loess was an aqueo-glacial deposit, marginal to the drift 
sheet now named "lowan." This work was published in 1882. 
This idea was subsequently amplified and given with more full- 
ness and detail by Chamberlin. 
The description by Todd and Bain, in 1895, of six feet of 
till, supposed to be of iceberg origin, intercalated in the loess 
of Iowa, would help to confirm the theory of fluvio-lacustrine 
origin of at least those deposits. 
The latest conclusions upon the subject of the loess are 
found in two papers of last year, one by J. A. Udden, the other 
by Professor Chamberlin, which agree in attributing the Mis- 
sissippian loess partially to eolian origin. The paper of Mr. 
Udden argues for the atmospheric origin in larger part. Pro- 
fessor Chamberlin holds that the loess was originally glacio- 
aqueous and only secondarily eolian, the latter in minor part; 
in these respects dififering from the Asian loess of Richthofen. 
Lake Basins. — Preglacial Drainage. — The problem of the 
origin of lake basins, especially those of the Laurentian sys- 
tem, has been so intimately connected with glacial studies 
that the subject should be mentioned. 
With the extreme views of glacial erosion that were cur- 
rent after the general adoption of the glacial theory of Agassiz 
it was but natural to attribute even larger lake basins to the 
gouging erosion of the ice sheet. That such is the genesis 
of many "smaller tarns and lakelets in areas of thin drift is ad- 
mitted. Geikie states this emphatically for Scotland, and Bell 
for Canada. Twenty years ago Newberry so explained the great 
lake basins, with Dana assenting somewhat cautiously. As 
late as 1894 professor Tarr thought that the Cayuga basin had 
been deepened 450 feet by glacial erosion. 
On account of the incidental character of the references to 
this matter it is doubtful where credit should be given for the 
earlier suggestions of the current views. As early as 1866 
Whittlesey recognized that the preglacial topography of the 
res-ion of the great lakes was in its broader features the same 
