ECONOMIC GEOLOGY. lOI 
Chapter VIII. 
ECONOMIC GEOLOGY. 
Even were the Splti valley rich in useful minerals, its inaccessibi- 
lity vi^ould be a fatal bar to profitable exploitation. 
Gypsum, 
As it is, however, the only mineral obtainable in 
any quantity is gypsum which, as already noted by Mr. Mallet,^ occurs 
at Huling and Changrizang in lower Spiti. It is also found in the 
valley of the Gyundi river in upper Spiti and between the Lipak and 
Yulang rivers in Kanaur. In the last-named locality it occurs in 
immense masses and thick beds replacing the carboniferous lime- 
stone (PI. XVIj. It is massive, very pure and soft, and could be mined 
with ease, but the cost of transport to the nearest market would be so 
high as to preclude the possibility of its competing with the gypsum 
of the Salt Range or of other mofe accessible localities. It is at present 
employed locally to some extent as a whitewash for the outer walls of 
houses, " chhortens " and " dukdens " (Buddhist shrines), but does 
not appear to be put to any other uses. 
Its origin has been discussed by Mr. Mallet in the paper already 
quoted. He attributes it to the action of the sulphurous thermal 
springs which are found near the gypsum ; the water of these, carry- 
ing sulphuric acid in solution, would act on the carbonate of lime of 
the limestones, thereby forming gypsum. That this explanation is the 
true one is proved by the fact that Mr. Mallet found the action still 
going on at the time of his visit, while the masses of gypsum near the 
Lipak and Yulang rivers are found to pass horizpntally into unaltered 
limestone, and to contain lumps and masses of that rock, thus show- 
ing that the change has taken place in situ. Analyses made by the 
present writer of the massive gypsum failed to show the presence of 
anhydrite. 
' Memoirs, G. S. I., vol. V. 
( 101 ) 
