Pleistocene Geology of Moravia Quadrangle 
403 
low gradient and a low ridge. The material constituting these 
two eskers contains a preponderance of coarse deposits; and the 
former, much till. This prevalence of unmodified drift suggests 
slight Water action. 
Esker No. 2 illustrates best of any the typical serpentine course 
which characterizes the paths of some subglacial streams. The 
meandering form is also excellently shown in portions of Nos. 
3 and 8. It is not well developed in eskers having either the 
lowest or the highest gradients. A great bulk of aggraded 
material, it is observed, is present where the sinuous course has a 
sustained development. Since the esker ridge is developed 
beneath the ice, the ice-cave being enlarged by ablation as the 
stream becomes more and more aggraded, the question arises as 
to the development of meanders. To what extent do the principles 
accepted as governing meander belts in subaerial streams obtain in 
the evolution of the sinuous esker ridges ^ It is very certain that 
a low stream-gradient does not account for the meanderings of 
the esker ridges discussed above. I do not believe the meandering 
of subaerial streams is induced entirely by a sluggish flow. 
Ice Motion. The location, direction and degree of develop- 
ment of these eskers, with probably one exception, indicate genetic 
association with stagnant ice. Nos. i, 2 and 3 are probably con- 
temporaneous in formation and indicate the interval of inactivity 
that followed the halt associated with the valley loop south of 
Freeville. Nos. 4 to 7, which were formed somewhat in the order 
named, have their genesis with the decaying lobe that reached 
southward through the Fall Creek valley. That none of these 
eskers attained a very marked development is due doubtless to 
the rapid decaying of this inactive ice. Esker No. 9 likewise 
represents the brief duration of a subglacial stream; the esker 
ridge is low, and its material, as already mentioned, contains a 
large amount of coarse ingredients, both characteristics indicat- 
ing an inactive flow of water. 
The only esker on the sheet that suggests a genesis not immed- 
iately governed by the underlying topography is No. 8. This 
ridge represents furthermore a considerable activity of the ice; 
brief mention has already been made of this fact. The middle 
portion of its course, which is convex to the southeast, is supposed 
to be normal to a line of the more vigorous ice which occupied 
the trough of Dry Run. It is supposed that the whole region was 
