Pleistocene Geology of Moravia Quadrangle 417 
and by Watson,®^ represents thelevelof Lake Warren. Its general 
altitude is 865 feet, but it blends westward into slopes, alluvial 
cone or delta in origin, that suggest a gradual lowering of the 
waters from the Lansing overflow channel. The sharper develop- 
ment of the delta, however, is associated with the lower level. 
‘‘F. Delta '‘F’’ correlates with “E’’ at Locke. More recent 
erosion has removed much of this gravel from one-half of the 
valley as far upstream as Montville. Post-glacial stream-work 
also has creased the northern slopes of the delta, revealing buried 
drift which often is very bowldry. The top of delta ‘‘F’’ has a 
gentle southward gradient. Both this fact and its frontal outline 
indicate a rather speedy decline in the level of the Lake Warren 
waters. Figure 23 gives an idea of the general outline of the 
delta viewed from the West wall of the valley. 
Smaller Deltas. The above list includes the more conspicuous 
areas of delta gravels. Each level thus indicated marks also the 
altitude of many minor accumulations of gravel at the mouths of 
secondary streams. These smaller deltas are particularly com- 
mon along the Freeville-Moravia valley. A delta fan of con- 
siderable size shows at Peruville, and apparently correlates with 
the lake level indicated by deltas ‘‘A’' and “B’’, overflowing by 
way of Turkey Hill. South of Locke, on the eastern side of the 
valley, several of these minor deltas show. Another marks the 
outlet of Dry Run, south of Moravia. 
Other Lake Phenomena. The dimensions of some of these 
deltas, particularly and '^E,” suggest a static body that 
endured for some time. When, however, we consider the torren- 
tial condition of drainage incident to the retreating ice-sheet, and 
the fact that load was easily acquired by all streams, there being 
little vegetation to retard degraclational agencies we realize that 
in a relatively short time a great quantity of gravel accumulated 
at the mouths of these streams. Consequently the other shore 
phenomena which we are accustomed to connect with water 
bodies did not attain much development in this quadrangle; some 
of the lakes had a brief existence; some were so slight in area that 
very little wave work was accomplished. 
In the valley south of Moravia, also in the neighborhood of Lake 
Como (fig. 15), and again southwest of McLean was noted the 
Loc. cit., p. r93. 
