Plate XV. 
LITTLE TAHOMA View of the rugged peaks from the divide between the 
P. M. McGregor forks of the Frying Pan glacier. July 30, 1912. 
The enormous amphitheater for which the Carbon Glacier 
is noted, Russell thought of as a sequential feature, developed 
by the cascading ice, and now threatening by the continued 
recession of its head wall into the heart of the mountain to 
seriously curtail the supply of tributary summit névés. As a 
matter of fact the cirque constitutes the real generatrix of the 
ice stream, and the latter’s fate does not at all hang upon the 
snow supply from above, as Russell thought. As long as the 
amphitheater catches a sufficient amount of wind blown snow 
the Carbon Glacier will continue to exist, even if the tributary 
néves on the summit were completely wiped out of existence. 
The Willis Glacier is closely similar to its neighbor the 
Edmunds Glacier and requires no special explanation. Both 
ice streams as well as the Carbon must be classed as cirque born 
glaciers; the only difference between them lying in the vaster 
proportions of the Carbon’s amphitheater, and these no doubt 
were determined by the superior size of the great hollow that 
originally existed in the mountain’s north flank. 
And now a word about another matter that even today 
is not generally understood. The precipitation on mountains 
of great elevation does not increase steadily upward all the 
way to the summit. As is well known to meteorologists the 
level of maximum precipitation is usually found at moderate 
altitudes, and therefore in many instances several thousand 
feet below the top. This is true also of Mount Rainier. The 
