256 University of Kansas Geological Survey. 
general appearance of this material is the same as that of the black 
sands so frequently found in connection with the placer gold mines 
of the west. In fact they are probably the same material. But 
being so much lighter than the gold dust which is associated with 
them in gold mining localities they have been carried to the east 
from their original home and have gone far beyond the limits of the 
gold which is mixed with the sand in gold mining localities. Many 
a citizen of western Kansas has had his expectations wrongfully 
excited on account of his superficial knowledge of the association 
of this black sand with gold dust in placer mines. He has neglected 
to consider that the higher specific gravity of the particles of gold 
would cause them to lodge much nearerthe mountain side than these 
eranules of iron oxide are found. As the result of this he has ex- 
pected that the presence of the iron oxide implied the presence of 
gold. 
Many samples of black sand have been sent to the University for 
examination, not one of which had the slightest trace of gold. 
Usually it is sufficient to make an examination with the microscope. 
But different individuals have so insisted on an assay that occa- 
sional samples of the black sand from western Kansas have been 
assayed for gold. Such assays have beeen made in the chemical 
laboratory of the University, and have invariably resulted in find- 
ing no trace of gold. 
| Clay and Silt.—The clay and silt vary in character from place to 
place and at different depths. Occasionally almost pure masses of 
clay are found, beds almost entirely free from admixtures of sand, 
clay with‘a high degree of plasticity, and which in every respect 
resembles the purest character of clay known, excepting sufficient 
impurities to modify its color. Frequently such masses of clay 
seem to be colored with decaying organic matter, as though during 
its accumulation organic matter in one form or another was present 
at least in limited quantities. Elsewhere the color of the clay seems 
to indicate the absence of organic matter of any kind. 
Volcanic Ash.—In a few localities a material exists in small 
quantity throughout the Tertiary of Kansas, which for years has 
been called “volcanic ash.” Under the microscope it appears to be 
composed of irregularly outlined thin flakes of a glass-like sub- 
