206 R. S. TARR AND LAWRENCE MARTIN 
Tanana and Delta rivers in the interior plateau. The samples 
described and the pictures shown are chiefly from the first of these 
localities, where the loess soil was clearly exposed in 1910 and 1911 
in the new railway cuts. 
Lithological character —Most of the eolian silt or loess is dark 
brown and made up of fine dust. The color is due to included 
fragments of vegetation, making the deposit resemble the peaty 
soil which is also abundant in the region. 
Professor B. Shimek, of the University of Iowa, who has been 
good enough to examine our samples, states" that they are not 
Fic. 2.—Exposure of loess soil or eolian silt near Chitina, Copper River basin, 
Alaska, with stump horizons. 
exactly physically like the loess of United States, one of them resem- 
bling the finest sand which sometimes underlies the loess. This 
coarseness of the material, which is clearly wind-blown, is what 
should be expected with the different conditions of loess- 
accumulation in Alaska and in the Mississippi Valley. 
The samples collected in Alaska by the authors have been 
studied under the microscope by Professor Edward Steidtmann, 
of the University of Wisconsin. They are made up of particles of 
various minerals, especially mica, a little feldspar, rare quartz, 
ferro-magnesian minerals, and some carbonates. There is no 
t Letter, December 23, 1911. 
