Notes on the Geology of Central Nebraska. — Russell. 39 
i — 
ance of the hills is another eriterion for distinguishing these beds. 
The bluffs are more angular than where there is a preponderance 
of sand. The contours are more pronounced and greater. Verti- 
cal and steep scarps will be found. This is not true of sand hills. 
excepting in a "blow-out" near their summits. This Loess-like 
soil is rich. Its vegetation is characterized by an absence of 
cacti, prickly pears, and soap weeds. The grass is even and not 
in bunches. The valleys are not closed, i. e., not valleys of wind 
erosion. Sometimes, and indeed not infrequently, The sides of 
.the hills are precipitous and not clothed with grass. The same 
cannot be said of sand hills although the vegetation upon the 
latter may be very scanty. No one, I think, will experience any 
difficult)- in recognizing the formation. 
The individual particles, entering into the composition of tin- 
beds under discussion, are quite uniform in size. This uniformity 
is pronounced in material taken from different localities. In 
general the particles are larger than those given by Messrs. 
Chamherlin and Salisbury in their report upon the Loess. In 
an examination of some 28,000 particles, I find the following 
results: Less than .014""", 24.0(10. Between, oil and .028 mm , 
about 4,000. A very few were over .028 mra . In the sixth an- 
nual report U. S. Geol. Survey at page 270, Messrs. Chamberlin 
and Salisbury give for Loess, of 150,000 particles, 97^- per cent. 
under .005""". It will be seen from the foregoing that the parti- 
cles from central Nebraska range perceptibly higher in size. 
In connection with this microscopic examination, the fact was 
noted that much of the material was water worn. The grains 
were rounded and smoothed. That much had been removed 1>\ 
attrition was evident. This fact registers another difference be 
tween this formation and the Loess. 
The chief element entering into the composition is quartz. 
There are also present hornblende, biotite, mica, glauconite, 
orthoclase. and many grains stained with peroxide of iron. In 
addition to these from some horizons volcanic dust is found. 
When the last named clement is present it is always in sharp 
angular fragments. It is also isotropic and no difficulty will lie 
encountered in its detection. Excepting this volcanic dust one 
would he impressed by the regularity with which the other mil) 
erals are found, even from widely separated Localities. 
This formation is rich in calcium-carbonate ; not only is the car 
