Chap. IX. ] associated xox-manganiferous minerals. 
217 
aluminous mineral occurs in close association with manganese-ores. ^ This 
is at Talevadi in the Belgaum district, where gibbsite, AI2O3.3H2O, is 
found as incrustations and infillings in cracks and cavities in the 
manganese-ore. The gibbsite must have been formed after the psilomelane, 
the aluminium oxide having been derived, in all probability, from another 
mass of the laterite close at hand. 
In several of the deposits of the gondite series of the Central 
^. J. Provinces there are intrusive veins, masses, and 
patches, of felspathic rocks of pegmatitic character, 
in which the felspar is usually microchne. In one case, namely at 
Satak II, the microchne was able to develop crystal faces owing to the 
presence of a vug-like cavity in the rock. The crystals range up to TScm. 
in diameter and are of a dirty whit€ colour. One of them that is especially 
well developed shows the basal plane, c (001) ; the prisms, m (110), 
and M (110) ; the brachy-pinacoid, h (010) ; the + hemi-macrodome, 
X (101), and a negative hemi-macrodome. 
On page 757 I have noted the occurrence in a complex quartzite, 
forming the ' countrv ' of the Chikhla deposit 
Sappnirine. r • 1 ' 1 e 11 • 1 ii 
at one part 01 its length, 01 a blue mineral that 
is to be doubtfully identified with sapphirine. 
As the result of the chemical alteration to which the rocks of the 
kodurite series in the Vizagapatam district have 
Lithoiuarge auu kaolin. , , . , , r 1 1 i 1 • 
been subjected large masses 01 hydrated alunun- 
ous sihcates have been formed. They are of various colours, white, 
yellow, pink, and lavender, and, when coloured, probably contain oxides 
of iron or manganese. The material can be designated by the term 
lithomarge, the name given to the firm, compact and apparently non- 
crystalhne variety of kaolin, 2H20.A]203.2Si02. For it must be 
noted that although the lithomargic rocks, as seen in mass in the 
quarries, seem to be very soft and friable so that they give rise to con- 
siderable trouble in the quarr}'iiig operations, yet often a hand-specimen 
can be trimmed out of a piece of the material when it is dry. A piece of 
the white variety was analysed by Mr. J. C. Brown, of the Geological 
Survey of India, with the following result (1*18% of moisture having 
first been removed by heating at 100 °C.) : — 
Combined water .... 13 08 
Silica . . . ... . 49-84 
Alumina ..... 36-96 
Lime ...... traces 
99-88 
» Rtc. G. S. I.. XXXV, p. I6», (1906). 
