EOLIAN ORIGIN OF CERTAIN LAKE BASINS OF THE MEXICAN TABLE- 
LAND. 
BY CHARLES R. KEYES. 
The arid region of western United States and northern Mexico is a vast 
expanse of plain out of which abruptly rise a multitude of lofty mountains. 
The landscape has been aptly likened to a sea bedecked with volcanic isles. Of 
the entire area the desert-plains occupy about four-fifths; the mountains one- 
fifth. Between the different mountain ranges the plains-surface is usually, 
slightly inclined towards the middle. These interment plains are commonly 
designated as valleys. 
Over much of this country the rainfall is so deficient that the surface waters 
never reach the sea. In all this vast region the through-flowing rivers are few 
in number and of comparatively small consequence, for they receive little or 
no lateral drainage of a perennial character. Little opportunity is given for 
the development of great drainage systems such as are found in other and 
moister parts of the world. Most of the waters that enter the plains from the 
mountains thus drain into what are practically enclosed basins. In the middle 
of many of the basins are broad mud-flats, or playas, and not infrequently 
lakes. Some of the lakes may be regarded as permanent bodies of water; but 
more often they are more or less ephemeral in character.^ 
Most of the enclosed bodies of water which lie in the middle of the inter- 
ment plains appear to be readily accounted for in the usual manner of lake 
formation. There are, however, many of the lakes and lakelets which are not 
situated in the lowest parts of the valleys, but are found well up on the more 
elevated portions, even near the foot of the mountains. Throughout the arid 
region there is constant recurrence of these phenomena. 
In the case of the last mentioned class of lakes the question naturally arises 
whether the lake-basins may not have been formed in other than in the usual 
way. In the arid country wind is now known to be the most efficient of the 
geologic agencies; water is quite secondary. In dry regions, also, wind is the 
chief planation process. It has been recently urged that wind mainly has 
sculptured the desert and given it most of its peculiar physiographic expression. 
The query then is; May not eolian influences have fashioned some of the minor 
lake-basins on the high parts of the plains; and if these, may they not have 
been also the principal agency in forming the playas and lake-basins in the 
middle of the valleys? There are strong reasons for believing that wind has 
actually been the most potent agency in this work. 
1. Am. Jour. Sci. (4), Vol. XVI, pp. 377-378, 1903. 
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