( hi AP XII.] 
KODURITE SERIES : GANJAM 
255 
List of lo'.alifAes for the members of the kodurlle scries. 
Quartz-orthoclase-rock.- Kodur, Devada, Peraiii, Garbham, Avagudem, and 
Ram«vbhadrapuiam. 
Ortlioclase-iock. — Kodiir and Garbham. 
Quartz-apatite-orthocla.se-rock. — Ramabhadrapuram. 
Quartz-kodui'ite. — Devada, Garbham, and Ramabhadrapuram. 
Kodurite. — Kodur, Devada, Perapi, Garbham, Kotakarra, Ramabhadra- 
puram. 
Pyroxene-kodurite. — Kodur. 
Biotite-kodurite. — Ramabhadrapuram. 
Spandite-rock. — Kodur, Garbham and C'hintelavalsa. 
Apatite-spandite-roek. — Kodur and Sandapuram. 
Pyroxene-spandite-rock. — Kodur, Perapi, C'hintelavalsa. and Taduru, 
Manganese-pyroxenites. — Kodur, Chintelavalsa, Taduru, and Kantikapilli. 
Graphite-bearing manganese-pyroxenites. — Chintelavalsa, Taduru. 
Vein-quartz. — Kodur. 
Pegmatite. — Devada, and Ramabhadrapuram. 
Ganjam District. 
In view of the fact that the garnet contained in the specimen of rock 
from Boirani, of which the calculated analysis is given on page 258, 
contains such a small proportion of manganese compared with the garnet 
found in the kodurite rocks of the Vizagapatam district, it seems at first 
sight doubtful if the Ganjam rocks be really the same series as the 
kodtirite series of Vizagapatam district. Considering, however, tiie 
similarity of the rocks of the two areas in their other constituents and the 
fact that they both give rise to manganese-ore deposits on alteration and 
are otherwise subject to the same kinds of alteration, it seems probable 
that the two series are genetically the same, the only difference being that 
there is a considerable difference in the composition of the garnets contain- 
ed in the rocks of the two areas as represented by the two specimens 
analysed. This difference may indeed be accidental and the analysis of 
a large number of specimens of these rocks from the two areas might 
show that there is a great variation in the composition of the garnets 
through the isomorphous replacement of one constituent of the garnet 
by another. But even if the manganese-garnets of the Vizagapatam 
rocks constantly contain a greater percentage of manganese than the 
manganese-garnets of the Ganjam district, the petrological and miner 
alogical resemblances of the rocks of these two areas are sufficiently 
close for them to be regarded as one and the same series until evidence 
to the contrary can be produced. Hence the term kodurite can be extend- 
ed to the manganese-silicate-rocks of Ganjam. 
