ALKALfS In Colorado 
35 
found their way from the surface into them. In order to have alkalis 
present in our soils it is not necessary to have a Cretaceous or any other 
shale formation present. We have them without these. 
It is true that a very large percentage of irrigated Colorado land 
lies within the Cretaceous formation but there is land of Pleistocene 
age completely separated from the Cretaceous areas and we have an 
abundance of alkalis in such lands. These alkalis are not all of the 
same character, but, so far as the ‘'white alkalis” are concerned, they 
are composed of the same salts that we find in the Cretaceous areas. 
I repeat what I have already said that there is no ratio between the 
amounts of these salts, but they may range from pure sodic sulfate to 
pure calcic or magnesic sulfiate. In “white alkali” the sodic carbonate 
and sodic chlorid never become predominant. We have conditions 
under which sodic carbonate is predominant and present in injurious 
quantities. The geological evidence in this case is strongly in favor of 
a very recent origin, in fact of its production at the present time. 
“WHITE” AND “BLACK” ALKALIS ON ADJACENT TRACTS 
A very interesting fact in this case is that we have the “white” and 
“black” alkalis in adjacent territories. While it is beyond the scope 
that I set for this bulletin, it may be permissible to give some details 
in this connection. Even though I am not able to designate a section 
line as the dividing one between the two areas, The actual division be¬ 
tween them, however, is very sharp, considered from the standpoint of 
productiveness. In the area of “white alkalis” we have such mixtures 
as the following: 
Pei’cent 
Calcic sulfate . 0.874 
Magnesic sulfate . 0.033 
Potassic sulfate . 3.217 
Sodic sulfate . 79.557 
Sodic chlorid . 7.373 
Sodic carbonate . 3.472 
Sodic silicate . 0.748 
Ferris Aluminic oxids . 0.130 
Excessive Silicic acid. 0.684 
Ignition . 3.912 
The water-soluble in this sample as collected was 8o percent. An¬ 
other alkali collected fromi the surface of this land consisted of calcic 
sulfate lo.o percent and sodic sulfate, including a little magnesic and 
potassic sulfates, 84 percent. This sample contained no carbonates. 
Still another sample contained 90.6 percent sodic sulfate, and another 
80 percent of sulfates with 14 percent sodic chlorid. Of those having 
80 percent of sulfates, 60 percent was sodic sulfate, and still another 
from the same ranch carried 78 percent mixed sulfates, 64 percent of 
which was sodic sulfate. This last sample carried 15 percent sodic- 
