74 
IOWA ACADEMY OP SCIENCE 
Explanation of Plate VII. 
Pig. 1. Section along wagon-road southwest of Farley, Iowa, in Sec. 23. T. 88 N., R. 
I. W. This shows two loesses separated by an oxidized line. The lower (post- 
Kansan) gray loess contains large iron-stained root- tubes, which terminate 
abruptly at the upper limit of this loess. The upper yellow loess is 
stratified and contains no root- tubes. (See p. 63.) 
Pig. 2. Section in Gaulocher’s brickyard in Iowa City, Iowa, showing two loesses very 
sharply separated but with scarcely a trace of an oxidized line between them. 
The lower is a gray post-Kansan loess with iron tubules. The upper yellow 
loess has gray vertical lines or streaks which resemble the lower loess, and 
which were evidently formed by the roots. In some cases the gray upper 
streak is continuous with the iron tube in the lower loess ; both having 
evidently been formed by the same root long after both loesses were 
formed. (See p. 63.) 
