Explanation of Plate XII. 



Fig. 1. .Shows the two loesses in section 3, near Decorah, Iowa. 

 (See p. 340). The two markers indicate the line of separation, here 

 quite sharp. 



The lower is bluish (post-Kansan) loess, and the upper is yellow 

 (post- Iowan). 



Fig. 2. The third exposure north of the Iowa river in Jefferson 

 township, along the Cedar Rapids and Iowa City electric line. The two 

 upper markers indicate the line of division between the uppermost loess 

 layer, and the Iowan sands below. The whitish band below this is only 

 a moisture band. The two lower markers separate the lower, fossilifer- 

 ous loess from the Iowan sand. There is a strongly oxidized band below 

 this, extending into the lower loess, and the latter is exposed to the 

 base of the cut. The portion of the surface with markers was scraped 

 to show the position of the several parts. (See p. 366). 



