15 
Another potassium mineral which has received consideration 
is Glauconite, a hydrous silicate of potash and iron. Originally 
formed by precipitation in the beds of oceans, it is brought within 
reach of mankind by the secular upheaval of these beds into dry 
land. Thin mineral suggests itself as a possible source of com- 
mercial potash by its wide distribution in large quantities in the 
so-called greensands 55 of many parts of the world, including our 
own State. In the Cretaceous rocks extending from G-ingin north- 
wards are considerable thicknesses of unconsolidated greensand 
consisting of a mixture of loose granules of quartz and glauconite. 
The latter mineral averages between seven and eight per cent, of 
potash and three facts make it attractive as a source of potash : 
Firstly, the loose nature of the mixture, which points to a mech- 
anical concentration being cheaply and easily feasible : Secondly, 
t he complete chemical inertness of the principal gangue, quartz : 
Thirdly, the chemical instability of the glauconite itself, which 
leaves it open to attack by many comparatively weak chemical 
agents. Here is a field for research distinctly inviting to West 
Australian eher nists. 
Beyond these two minerals the only other common mineral 
which suggests itself as a source of potash is Muscovite, the potash 
mica. Here again we have a mineral carrying from seven to 10 
per cent, of potash but very stable and inactive, and presenting 
most, if not all of the difficulties of treatment of Felspar, whilst 
at the same time less frequently concentrated than the latter. It 
is quite possible, however, that the extraction of potash from mica 
may be simpler than from felspar, and if it should prove to be so, 
considerable quantities of mineral would be available for treat- 
ment, particularly if it could be treated in conjunction with felspar. 
To complete the survey of the possible sources of potash in 
the lithosphere it was necessary to consider quite another problem 
altogether. This is the atmospheric weathering of rocks and the 
connection between this process and the nature and quantity of 
the dissolved salts in underground waters and, ultimately, in the 
waters of the ocean. I have already drawn your attention to the 
fact that the Darling Range granite carries in its un weathered 
state one million tons of potash in every square mile 10 feet deep. 
In addition, it carries about three-fifths million tons of soda. Now 
if one pays a visit to any clay or gravel pit in these ranges one finds 
that the granite is completely weathered over large areas to a depth 
of at least 10 feet, often much deeper, and that the residual material 
carries only traces of alkalis. A study of the processes of weather- 
ing leads one to the conclusions (1) that all these alkalis have been 
dissolved in surface and subsurface waters : (2) that they have 
not been reprecipitated in the immediate vicinity. What lias 
become of all this dissolved potash and soda ? The soda I think 
can be quite satisfactorily accounted for by the soda of the ocean, 
