368 The American Geologist. "^""'^- ^^'^^• 
Keddisli clay, passing below into twenty feet till which 
is yellowish above, but the blue color rises in places 
near the top 11 
Levci of the river. 
In speaking of the highlands west and south of Todd val- 
ley, I. S. Crawford states : "The formations in the highlands 
west of the valley are nearly identical with those to the east, 
but water rises within a few feet of the surface. These con- 
ditions hold good for wells as far west as R. 6 and to the south 
line of T. 14, beyond which the conditions vary. We get flow- 
ing wells in the southwestern corner of the county ; also, saline 
wells, but not too salt for stock, m a sand rock in T. 13 east of 
the west line of R. 6." 
Conclusions. — The observations enumerated, if understood, 
indicate the presence of a flood plain buried beneath the loess 
in Todd valley, and show that it is nearly identical in struc- 
ture with the Platte flood plain. The highlands are very un- 
like the flood plain of Todd valley in structure. Rock beds of 
the former occur in a higher level than the buried channel. 
That the valley was eroded in Glacial, Benton, Dal^ota and 
Probably Coal Measures beds, is quite apparent. 
Origin of Todd Vail ex. 
All evidence cited goes to show that the valley was pro- 
duced by the Platte river at an earlier period. The topography 
and stratigraphy both indicate that fact. The elliptical high- 
land cannot be a river-island such as now occur at a num- 
ber of places along the river. The structure is identical with 
the other highlands from which it has been separated by eros- 
ion. It denotes a distinct change in the earlier course of the 
river. Just what the history of that change in drainage is, I 
do not know. Neither do I understand the causes of the diver- 
sion. The question is a complicated one. Professor Todd, in 
Bull. 158, U. S. G. S., 1899, p. 143, writes the following: "The 
relations of the high terrace of the Platte river to the high- 
land in the vicinity of Fremont, Nebraska, suggests that the 
diversion of the old channel across Saunders county mav have 
been due to its cutting through the divide which formerly sep- 
arated the Platte from the Elkhorn, and that this was subse- 
quent to the formation of the terrace." Slow elevation to the 
west at that time must have given the river increased velocity 
which may have caused it to cut through the divide. 
