Chap. III. ] 
PYROLUSITE. 
81 
most famous is that of Gosalpur in the Jabalpur district, Central Provin- 
ces, for analyses of which see page 813. The masses of pyrolusite foiind 
at this place are sometimas as much as 1 to H feet in diameter. When 
broken open they are usually found to be partly cavernous with small 
crystals of pyrolusite lining the ca%'itie3. Of the fine specimens in the 
Geological Museum, Calcutta, it is not, however, certain which have been 
derived from the laterite at Gosalpur and which from the nests and pockets 
of this mineral that occur in the Gosalpur quartzdtcs. Fair quantities 
of pyrolusite have also been foimd at Mansakra in the same district. 
Pyrolusite is also sometimes formed as a recent deposit, for an 
example of which the occurrence at Pan Kuan in the Dhar Forest may 
be cited (page 675 and Plate 15). Here the ipineral is associaterl with 
what is probably tufa. 
The black dendritic markings of manganese oxide often found on 
the bedding and parting planes of rocks are usually referred to pyrolusite ; 
the best Indian examples are those found on the bedding planes of 
Vindhyan sandstone ; see Plate 4, which is only i; natural size. 
Dendrites are often found in the Indian manganese mines. 
In the following table T give some analyses of picked specimens of 
. , Indian pvrolusites. The first specimen was sent 
Analyses. - . . . •'■ . . 
from Bikonhalli in the Shimoga district, Mysore, 
by Mr. C. S. Fawcitt. The pyrolusite formed a magnificent black lustrous 
crust of small crystals resting on cavernous ore composed of limonite, 
pyrolusite, psUomelane, and manganite (?). Some of these crystals were 
detached and carefully picked. The analysis was kindly undertaken by 
Mr. Fawcitt. The second specimen was sent by Mr. H. J, "Winch from 
Ghatia in Banswara State, Rajputana. It showed some rather dull, 
longish, prismatic crystals of nearly square form implanted on 
some fine-grained manganese-ore, probably composed of a mixture of 
braunite and psUomelane. These prisms gave a black streak, were 
scratched by fluorite, and gave off a Uttle water in a closed tube. The 
specific gravity of some of these detached prisms was found to be 4 • 94, 
a little high for pyrolusite. The analysis of the picked sample was under- 
taken by Mr. Fawcitt. The third specimen was obtained from a heap 
of picked ore at Kodur in the Vizagapatam district, Madras. It was a 
fine-grained crystalline piece of ore with cavernous spaces lined with 
shining mammillations of pyrolusite. The piece taken for an.'vlysis was 
some two inches in diameter, but its specific graA-ity was not determined 
on account of the soft and friable charactpr of the mineral. Thia 
I G 
