120 
MANGANESE DEPOSITS OF INDIA : MINERALOOY. [ ParT I : 
in the form of lithomarge or kaolin, and perhaps partly as potash-felspar 
only partially converted into kaolin, laking the first analysis it is found 
that the composition can be represented as follows : — 
Specimen No. A. 2'4l. 
Orthoclase 6 "99 
Albite 314 
Kaolin . . . . . . . 2 "50 
Apatite . . 0 458 
Psilomelane . . ...... 85 '50 
Quartz . . . 3'10 
Sulphur 0-016 
AS2O5 .... 0-026 
Ti02 0-06 
Moisture ... ..... 1 -55 
103-340 
Oxygen assumed ........ 3 "36 
99-980 
From the large amount of oxygen, namely 3-36, below that required 
for the formation of psilomelane. it follows that this wad is not a mixtvu:e 
of manganates (psilomelane) with the other constituents orthoclase, albite, 
kaolin, and quartz ; but that it is in all probability an indefinite mixture 
of oxides of manganese, iron, etc., with partly kaolini7ed felspar. In 
the same way the analysis of the Kodm" wad can be calculated into a mix- 
ture of 6-43% of kaolin with psilomelane, the latter making up the bulk of 
the residue. But, as before, there is too large a deficit of oxygen, in this 
case 1"94%, so that this wad also is probably to be regarded as a mixture 
of oxides. On page 1090 is given an analysis of a specimen No. A. 228, 
collected at Gfirbham, that seems to be physically inter ediate etween 
psilomelane and wad. It is very porous and has a specific gravity of 
4-O8. It contains scattered through it a fair quantity of tiny specks of a 
magnetic mineral, which is probably manganmagnetite. As is show on 
that page, the analysis can be re-arranged so as to consist of 5-57°/o of 
kaolin, 10-45% of mpgnetite, and 82-2Po of psilomelane. with no excess 
or deficit of oxygen. It is not certain, however, that this is the correct 
interpretation ; for the specimen may be only a mixture of oxides similar 
to the specimens noticed above. The chances, however, are in favour of 
its corrcctness,and it seems that this specimen is to be regarded as psilome- 
lane just passing from the wad stage of indefinite mixtures. It is still 
soft, however ; but might have become harder later on by a more com- 
