220 
IOWA ACADEMY OF SCIENCE 
ing, such a term agreed upon will be welcomed by the writer ; but Dallas 
deposits is the term which at present appears to him most acceptable. 
The significance and bearing of the important fact mentioned in the 
above description of the Sandyville section, where a lower portion of 
the gumbo is described as presenting evidence that an upper portion 
had been pushed along over the lower, should not be overlooked. Such 
a relation has been used .elsewhere as part of the evidence that an under- 
lying drift is sub-Aftonian. Here the underlying drift is Kansan. 
This is the first time the writer knows of that such evidence has been 
presented of two movements in the Kansan itself (including the gumbo 
as a part of the Kansan drift.) 
In places the low ground gumbo does not belong to the Dallas deposits 
but is a worked-over Dallas deposit washed from the higher ground 
along ravines and into the low ground, where a deposit similar to the 
gumbo of the upland may be found without a trace of stratification. 
The brownish, laminated clay charged with plant fibers near Coon 
Valley (No. 3), and that crumbly and iron stained deposit without plant 
fibers near Hartford, seem related in time and possibly in conditions 
of deposition. The lower boundary of each is hard to distinguish from 
the, gumbo: but the deposits are easily distinguished from the overlying 
silt-like deposits in the places named. They seem to mark varying 
conditions in an old land surface. In places dark bands appear at the 
surface, and in places traces of oxidation. 
The loess. Distinct loess is only found in the northern portions of 
the area. The general difference between the brown and 1 the gray por- 
tions seem due to weathering. It is also recognized that during the 
deposition great changes in climatic conditions took place which might 
affect what was surface at that time. Such is the similarity between 
weathered gumbo and weathered loess that it may be a portion of the 
soil in the southern part of the area should be described as partly loess; 
the* deposit there immediately beneath the soil is gumbo. 
