208 R. S. TARR AND LAWRENCE MARTIN 
12 inches in diameter. Some of them show 160 rings of annual 
growth. As there are 7 or more generations of such buried stumps, 
Fic. 3.—Five or six generations of stumps buried in loessian deposit near Chitina, 
Alaska. 
this suggests that the region has been deglaciated at least 700 to 
1,000 years as a minimum, for during at least this period the eolian 
deposit has been accumulating. 
