Pleistocene Geology of Moravia Quadrangle 363 
lations of drift. This marked development continues to barricade 
the valley almost to McLean (fig. 21) a distance of fully three- 
fourths of a mile. At McLean the bottom of the valley again 
presents the wide flood plain appearance already alluded to north- 
east of Freeville. This accumulation of drift represents rather 
more perhaps than the mere halt of a valley tongue or lobe of ice. 
Its general appearance, however, in crossing the valley tends to 
bring the drift under the category of valley loops. A fuller dis- 
cussion, however, of this particular area is g ven under Karnes, 
since the predominating type of drift in this area is the kame. 
‘‘K.’’ Proceeding northward from McLean one notes the 
rather constant mass of drift that the valley carries, more espe- 
cially along its western wall. The three highways that terminate 
in the east-west road passing through Nubia cross the drift just 
alluded to. The easternmost of these highways cuts through 
less glacial material than the other two; in fact, during the last 
half mile before reaching Nubia, the rock slope is slightly mantled. 
At the village of Nubia, however, the position maintained by 
the ice-front is more strikingly shown; a wall or ridge of drift pre- 
sents a convex outline as we proceed northward and for a quarter 
of a mile it is evident that the ice receded very slowly, as one is 
able to easily decipher briefer but very clear halts. Here, too, 
the bulk of the drift flanks the western wall of the valley. 
‘‘L.” For about two miles, as we proceed northward, the 
drift on valley bottom and the side walls is monotonously uniform 
approaching Rogers Corners, east of which place there enters the 
major valley from the east a fairly mature tributary. The posi- 
tion which the ice maintained, with two tongues abutting the rock 
salient that extends northward between these valleys, is most 
plainly seen in the location of the drift ridges across the two 
valleys. Fig. 12 shows the appearance of a valley loop in the 
tributary valley; the ice-front drainage here was not as free as in 
the major stream. Furthermore, the topography to the east 
tended to concentrate into the tributary valley a large amount of 
drift brought by streams aligning the flank of the ice tongue; 
hence, the more conspicuous development of this latter loop. 
‘‘M.” For the next mile northward the flood plain is not 
interrupted by ridges of drift, but just south of Lake Como, 
where the highway forks across the valley, a stationary position 
of the ice is read in the band of drift that intercepts the outwash. 
