Frank Carney 
408 
the present course of Fall Creek between these villages is an 
indication of the irregularly deposited drift that there fills this 
valley. This lake, if it persisted long enough, must have tended 
to level off the drift hills approximating its altitude. 
‘‘ B. This delta is about one mile north of Groton on the east i 
side of the valley. The triangular area marked off by highways 
lies entirely within the delta. Its slope is gentle, rising from about 
1010 feet at the margin to 1035 feet eastward; its area is approxi- 
mately a square mile. As the lake in which these sediments were 
laid down gradually lowered, the delta-forming stream from the 
east evidently hesitated between two courses. Along its eastern I 
margin running southward is the course of a temporary water- 
way, while the final course taken by the stream from the east has i| 
dissected the northern portion of the delta. Thus the body of ! 
the delta has remained intact. (Fig. 9). i 
‘‘C. ’’ This delta is adjacent to morainal loop "‘F” (p. 358); 
it lies on the same side of the valley, but one and one-half miles | 
north of ‘"B.” Its general level is 1120 feet. Along its north- ! 
western side there is an ice-contact slope; here also clay is abundant | 
in the delta plain. In genesis, then, this delta is closely associated | 
with a halt of the valley tongue. Further consideration, however, 
is given this point in the section where I discuss the static bodies 
represented by these deltas. | 
‘‘D.’’ This delta is in the valley bottom about a half-mile 
southeast of North Lansing; it has but slight development, never- | 
theless it is typical both in outline and in surface slope, ranging i 
from 980 to 1000 feet. The delta was laid down by a stream j 
flowing from the east. Its serrated front as well as the valley | 
bottom to the west contains a conspicuous quantity of sand. 
'‘E.” South of Locke is a delta approximating two square i 
miles in area, and ranging in altitude from 855 to 905 feet, j 
Obviously it represents the work of a stream flowing from the | 
west (fig. 22), and the development evidently attained is not due j 
entirely to stream deposition. A few scattered sections, particu- | 
larly along the eastern margin of the delta, disclose deposits of till, !| 
showing that the load of the stream emptied here into a static 
body has tended to even up the former irregular morainic topography 
in this triangular area. In this connection I would mention 
the fact that practically the whole delta surface is unusually ston), 
attesting the torrential character of both the major delta-making 
