IOWA ACADEMY OF SCIENCE 
255 
The cut is about 250 yards long and attains a maximum depth of 20 
feet. One hundred twenty yards of the east end is till, 100 yards of the 
west: end is yellow fossiliferous loess, and between these are the con- 
torted folds and rolls of Buchanan gravel in peculiar relation to the 
Kansan below and overlain by 2 to 8 feet of till. The arrangement of 
the materials is shown in Fig. 4. 
The oldest material in the cut is Kansan till— blue at the bottom and 
grading up in places into a grayish to yellow color according to the 
degree of weathering. The blue drift is very clayey, contains small peb- 
bles, many of which are greenstone, and breaks with polyhedral fracture. 
Joints are prevalent in the yellow clay and in the upper part of the blue, 
but instead of being vertical they dip to the west, suggesting that they 
are the result of pressure from that direction. In that case they might 
be regarded as slight shear-planes resulting from the same force that 
produced the distortion of the gravels above. Overlying this, in a pe- 
culiarly folded and contorted manner, is Buchanan gravel, the textural 
range of which is from fine flour to bowlders 1 foot in diameter. The 
gravel exhibits the oxidized, weathered, and decayed character common 
to the Buchanan, iron-stones being not 'uncommon and cementation by 
iron oxide sufficiently prevalent to have preserved stratification lines at 
many points. 
Referring to Fig. 4 from left to right, the gravel appears at (1) in a 
narrow band and rises at an angle of about 45 degrees to a point near the 
top of the cut, from which it takes a horizontal course and assumes va- 
rious forms of folds and loops to where it ends rather abruptly against 
till. 
A striking feature of this cut, besides the contortions, is the fact that 
the gravel deep in the cut is as much weathered as that near the surface, 
whereas the till is not. Also at several points there is no gradation of 
weathering from the gravel into the underlying till. At (1) the gravel, 
so altered that some bowlders can be picked to pieces by the fingers, rests 
against the blue unweathered till; along the lower contact of (2) and 
around the lenticular body (3) the contact is sharp; and around the 
lower part of (4) and between (4) and (5) the till is scarcely changed 
whereas the gravel is much altered. 
Overlying the gravel is a yellow, blue-streaked till, 2 to 4 feet thick 
along the summit and attaining a thickness of at least 8 feet along the 
west monoclinal limb. On the western slope of this, beginning at the 
point (X) and lying in contact with the drift along a diagonal line 
(made clearer by dotting), lies yellow fossiliferous loess which is not 
