IOWA ACADEMY OP SCIENCES. 
87 
The strong northwesterly winds blowing over the prairies, 
which during a part of the year at least were quite dry, gath- 
ered up clouds of sand and dust. The coarser material was 
blown and rolled about on the surface, the constant grinding 
furnishing renewed supplies of finer material, while this finer 
material was carried higher, being finally swept over the for- 
ests, and there deposited. 
That this is not a fanciful view of the work actually per- 
formed by winds has been nicely demonstrated in eastern Iowa 
during the past two years. High winds prevailed during con- 
siderable portions of both years, the dry spring of 1895 being 
particularly remarkable in this respect, and observations upon 
the material so transported were made in Johnson county. In 
the northern prairie portion of the county, beyond Solon, fine 
sand was heaped up in open places, in some cases to a depth of 
over a foot, within twenty-four hours, while fine dust only was 
carried into adjacent groves, and was there deposited upon 
every available surface to a depth of not less than one mm- 
The writer’s observations of the effect of the winds which so 
prevail in Nebraska also confirm this. 
That this fine material now constituting the loess, was so 
deposited in forests is further shown by its distribution. That 
the loess and the original forest area in eastern Iowa almost 
exactly coincide is a well established fact, which has been 
demonstrated beyond question by McG-ee.^^ 
The forests are found along the streams, and also principally 
on the southern and eastern slopes of the hills, and the loess is 
found in exactly the same situations. 
Indeed it has often been suggested that there is something 
peculiar to the loess which renders it favorable to the develop- 
ment of the forests — whereas the fact seems to be that the 
forest is especially favorable to the deposition of the loess if 
lying adjacent to or near drift- covered plains. 
That the forest could have preceded the loess is shown by 
the fact that scrub growths of bur oaks have been able to gain 
a foothold along the shores of some of our northern (Iowa) 
lakes and streams in a purely glacial soil, thus forming the 
nucleus of a forest in comparatively recent time, while in the 
same region in groves evidently somewhat older a thin layer 
Interesting observations were made in 1894 by F. H. King (see Eleventh An Rep of 
the Wisconsin Agr. Ex. Sta., p. 292 et seq.) upon the effect of winds on vegetation in drift- 
ing soil which hear out the conclusions presented in this paper. 
15U. S. Geol, Sur., 11th Ann. Rep., Part I, pp. 296, et seq. 
