192 The American Geologist. Sei.i. iuIkt. 1902 
nant of a terrace risinje;- about 125 feet above the river, the 
contents of which are loess, but at the base becoming too sandy 
and coarse to warrant that name. Again, laetween Council 
Bluffs and Sioux Cit}-, as mentioned by Mr. Upham, another 
terrace about 20 feet above the river borders the river on the 
east side for many miles. The Missouri Valley Railroad is 
located on it. There is at hand no evidence as to the nature of 
this lower bench — whether it consists of diift materials or 
of rock, and if of the former whether it is a residuum of the 
general loess sheet due to a halting shrinkage of the Missouri 
from its loe^sian stage or to a constructural refilling subsequent 
to its deeper excavation. ]\Ir. Upham regards it, at least in a 
tentative manner, as a constructional terrace of later date than 
the general loess, and probably due to the high waters of the 
^^^isconsin ice-sheet then existing further north. In the absence 
of knowledge of the nature of these terraces, either or both of 
which may have once existed at Lansing and at the Concannon 
farm, the only recourse is to accept the determinations and 
classification of the lowan geologists as to the origin and date 
of the loess covering the tomb of the Lansing man. 
The general loess sheet of the Missouri valley, in western 
Iowa and in northwestern ^Missouri, and in the adjacent por- 
tions of Nebraska and Kansas, presents such uniformity of 
character that it seems necessary to ascribe it to a single cause 
and apparentl\- to the same date. Still Prof. J. E. Todd has 
suggested that* it is divisible into two parts : an upper loess, 
coA-ering the uplands, and a lower loess restricted to the valley 
of the river, the latter being much the younger and forming 
a terrace which rises about 125 to 150 feet above the present 
level of the river. Such terrace has already been mentioned at 
Council Bluffs. It is indicated on the Omaha side of the river, 
viewed from Council Bluffs, by the jog in the distinctness of 
the timber line. This terrace must have extended to Lansing 
and its relative date, as compared with the upland loess, plays 
an important part in the question of the age of the loess over- 
lying the skeleton. 
In any case, accepting the determinations of the geologists 
of Iowa, and the time-ratios of Prof. Chamberlin. the loess 
of the river at Lansing can be no more recent than the date of 
* Missouri Geological Survey, xo\. x, p. 128. 
