Lansing Pleistocene Geology. — Jrinchell. 293 
I visited the Lansing locality last December with some expectation 
that the remains might prove to have come from the base of the ter- 
race corresponding to that shown at Kansas City, where some remains 
of mammals have been found. In such a case it would have been 
reasonably evident that they dated from early Wisconsin time. In- 
stead I found them outside of the trough of the Missouri in the base 
of a deposit forming an ill-defined shoulder in the valley of a small 
tributary which rises twenty-five to thirty-five feet above the flood 
plain of the Missouri. It is reasonable to account for the indefiniteness 
of the shoulder by wash added from the hillside back. The deposit 
there is of a grayer tint than that upon the hills back, which is rusty 
and sandy, resembling thaj: on the east side of tne Missouri in this 
latitude. The bouldery drift is very thin. It is probable that the ice 
sheet never reached quite so far as this. It seems possible that the 
pre-glacial valleys were never perfectly filled in the loess stage, wdiether 
it was lowan, Illinoisan or late Kansan, and that the water ways were 
revived along the same lines as before. Then followed a period of 
rapid erosion of the Missouri valley and a deepening of its tributaries 
much beyond any former trenching, another filling to the hight of the 
terrace outlined above, and again excavation of the sediment, which 
may not however have extended far up the tributaries. We might 
think the deposit under special consideration to have dated from such 
a stage, were it not so near the present level of the river. As it is, it 
seems to me altogether more rational to consider it the extended apex 
of an alluvial cone, or the "handle,"' so to speak, of an alluvial fan 
formed by the creek when the Missouri channel was on the east or 
opposite side of its flood plain. I could refer to several such deposits 
in Fremont and Mills counties, Iowa, some rising to fully as great a 
hight above the Missouri. Then the return of the Missouri to the west 
side w^ould result in the cutting down again of the tributary as it is to- 
day. Nor would it require more than a few centuries to accomplish 
such a c}'cle, under favorable circumstances. 
2. The evidence in favor of a deep preglacial valley seems to me 
hardly complete. The fact that the bottom of Ihe trough of the Mis- 
souri opposite has been reported ninety feet below the water level 
does not prove that the river has ever been lower than at present. 
Scour to that depth has been observed at Nebraska City by Mr. L. E. 
Cooley, in 1879.* 
The well twenty- four feet deep reported by Mr. Concannon is the 
strongest evidence, but is it possible that soft shale underlies the lime- 
stone there? 
3. When I \isited the locality there was a narrow tunnel running 
with the main one, and west of it extending north from the cross tun- 
nel. .\s it is not hinted at in Chamberlin's paper and you say nothing 
of it I judge that it has been dug more recently, possibly to obtain 
earth to close the cross tunnel. Its bottom shows an abrupt drop in the 
surface of the rock floor of about two feet. How would that affect 
* Report of U. S. Eni^ineer-i fur 1879 80, part 2. pp. 1066, 1071. 
