G(50 
MANGANESE DEPOSITS OF INDIA : 
DESCRIPTIVE. [Part IV : 
Where the road from Champaner to Jambughoda cuts through these 
^ . od on (at point E on map) a very instructive 
section — doubtless the one seen by Blanford. It 
consists of alternating quartzites and sandy slates very much folded, so 
that in the course of some 250 yards several anticlinal and synclinal folds 
are to be seen. The quartzites are fine-grained, compact, pinkish, yellow- 
ish, and white, break with a conchoidal fracture, and have mostly been 
more or less replaced by manganese oxide deposited from solution percola- 
ting along the bedding and joint planes ; consequently the exteriors of the 
various blocks are blackened to a depth of from ?, to 3 inches, whilst the 
quartzite inside is sometinies decomposed and friable, and sometimes 
almost quite fresh. The blackened rock may be either soft or hard ; in the 
latter case it has a dark grey fine-grained appearance. A microscope 
section of the latter shows that it really consists of a net-work of oxide 
of manganese sweeping round and enclosing remains of the separate tiny 
quartz grains composing the quartzite. Fig. 1 of Plate 10 shows a 
photo micrograph of the junction between a part of the rock that has 
not been darkened by the manganese oxide, and a part that has been 
completely blackened. 
On the rising ground just to the south of this road section a series of 
specimens could easily be collected showing a gradation from a quartzite 
with a few black manganiferous spots, through black manganiferous 
quartzites with residual patches of unblackened quartzite, to the wholly 
black rock. As might be expected, this impregnation and replacement 
by manganese oxide has proceeded to different depths in different places. 
On the north side of the road on the top of the hill F is another outcrop 
of quartzite and manganese-ore. A sample was taken of the latter, partly 
from the outcrop and partly from the debris scattered on the 8. E. slopes 
of the hill. The majority of pieces of ore were pyrolusitic in nature and 
some of them contained a little residual quartzite. The sample pelded on 
analysis (J. & H. S. Pattinson) : — 
Sample No. A. 47. 
Manganese peroxide 
Mangane.se protoxide 
Ferric oxide . 
Baryta 
Silica (combined) . 
Silica (free) . 
Phosphoric oxide . 
Water (combined) . 
Moisture at 100° C. 
43-98 
3- 09 
4- 35 
0- 33 
1- 9.5 
38-70 
0- 40 
1- 95 
0-40 
