392 C. Whittlesey—Pre-Glacial Channel of Eagle River. 
Within the cafion proper two antagonistic elements ever 
work. The greater number and extent of tributary glaciers 
on the northerly slope will increase both ice and debris there, 
and thus tend to deflect the stream northward and build up the 
southern moraine; while on the southerly slope the greater 
variability of temperature will augment disintegration and the 
more effective reflection and radiation will accelerate the flow 
on that side, aud thus tend to deflect the ice-stream southward 
and build up the northern moraine. 
The modifications in the action of the general law due to 
external conditions are, accordingly, not such as to affect 11s 
validity or materially reduce its potency. 
The law of meridional deflection of ice-streams here re 
appears adequate to explain the common curvature of the 
moraines of the Sierras. 
February 18, 1883. 
Art. LIL — The Pre-glacial Channel of Eagle River, Kewee- 
naw Point, Lake Superior ; by CHARLES W HITTLESEY. 
INTRODUCTION. 
IN the year 1854, the author examined the scattered and 
mutilated maps made in the progress of mining at the Ph Me 
location, on Keweenaw Point, Lake Superior, and compue 
i i i eri 
some discoveries relative to an ancient and deeply-buried 
channel of the Eagle River. At that time such facts were 
regarded more as curiosities than as valuable data. Recently, 
however, more attention has been given to this class of ph 
nomena, and all facts relating to the ancient drainage ben? 
are r as having permanent value. So much of ihe 
report as relates to this subject is, therefore, now given t0 * 
scientific public with some unimportant modifications, ™% 4 
for the convenience of the reader, who might not otherwis 
readily understand some of the references. The maps 9 
sections have been reduced and somewhat simplified by the 
elimination of matter not deemed important to science. 
