1052 
MANGANESE DEPOSITS OP INDIA : DESCRIPTIVE. [ pART IV 
limits of Kondakoduru (or Kondapalem) and partly in Duvvam, 
none of the excavations being within Koduru village limits. 
As is shown in the map (Fig.^79) of this area, parallel bands of 
rock showing a similar change of strike lie on either side of the 
manganiferous belt. On the N. E. side of the ore belt occurs a belt of 
wollastonite-scapolite-gneiss (composed of wollastonite, >capolite, green 
pyroxene, brown garnet, with subordinate calcite, felspar — both ortho- 
clastic and plagioclastic — , quartz, and sphene), which crops out in a 
series of small hills and tors of barren blackish aspect (one of these hills 
is shown in Plate 50, fig. 2). These gneisses are so folded and vary .?o 
in dip that it is extremely difficult to say if they dip under or over the 
ore-belt. Forming another curve outside the gneisses is a belt of khon- 
dalite (graphite-garnet-sillimanite-quartz-schist) marked by the three hills 
shown on the map at a distance of 1 to H miles from the ore- belt. 
In these hills also the dip is variable, being to the E. N. E. in the most 
southern one and to the S. W. and S. S. W. in the middle and northern 
ones respectively. Furthc to the east of this khondalite belt gneissose 
granite comes in 
On the S. W. side of the manganiferous belt there is a repe- 
tition of the rocks seen to the N. E. of the belt. The scapolitic 
gneisses are exposed on the low ground to the west of the Devada 
and Sandanandapuram quarries and presumably continue to 
the N. W. where, however, the ground is obscured by alluvium. 
Although the rocks are much disturbed, still it is evident that the 
general dip of this belt is towards the ore-belt. To the 8. W. of 
the gneiss-belt is another of khondalite dipping under scapolitic 
gneisses and marked by the ridges to the west of the Devada and 
Sandanandapuram quarries. To the S. W. again of the khondalite 
is gneissose granite. 
Hence a section along the line XY of Fig. 79 might be as in Fig. 80, 
m which the ore-zone is composed of very felspathic rocks carrying 
bodies of manganese minerals and intruded along the bedding planes 
of the scapolitic gneisses. The repetition of similar rocks on either 
side of the ore-belt may, however, indicate an overturned synclinal, 
through the base of which the felspathic and manganiferous rocks have 
burst, as shown in Figure 81. 
