LAKE BASINS CREATED BY WIND EROSION: 
InN various parts of the Great Plains lakelets are somewhat 
abundant. At the north some of them occupy hollows in the 
uneven surface of the drift; elsewhere they are imprisoned by 
the unequal heaping of sand in dunes. 
Those of a third class are independent of drift and dunes, 
and their explanation is not so readily apparent. They are so 
shallow that one may wade across them in any direction. They 
have no outlets and no permanent inlets. Their catchment basins 
are small. Ordinarily their basins interrupt divides between 
stream valleys, and they often rest on the highest tables of their 
vicinity. They are not permanent, but appear and disappear as 
storm and drought alternately prevail. Some basins are ordina- 
rily dry, holding water only for a few days or weeks after a thun- 
der storm. The lakes of others are approximately perpetual, 
disappearing only after a succession of dry seasons. 
During the summers of 1893 and 1894 I rode extensively 
through a district in the Arkansas basin where these lakes are 
somewhat abundant; in one rectangular tract containing less than 
1000 square miles twenty were noted. Various hypotheses as to 
their origin were considered, and at the end of the first season 
wind action was preferred, but less because its process was under- 
stood than because each other suggested hypothesis seemed 
barred by some insuperable obstacle. In the second season, 
however, some allied phenomena were observed which seemed to 
throw light on the subject and served to strengthen the hypothesis 
of wind action. 
The rocks of the country include a sandstone and two lime- 
stones which constitute the crests of the uplands, but the greater 
part of the surface is occupied by shales. The shales sustain a 
scanty growth of grass, with here and there a shrub and, more 
tRead to the Geological Society of America, December 27, 1894. 
47 
