180 HOLLAND* SIVAMALAI SERIES. 



the crushed rock are highly magnetic, but give also reactions for 

 titanium when tested chemically. 



The graphite) separated by means of Sonstadt's solution from 

 a weighed sample of the crushed rock, was found, after thorough 

 cleansing with hydrofluoric acid, to amount to 0*58 per cent., which 

 in so light a mineral occurring in thin plates is as much as might 

 be expected from the show it makes in hand-specimens. Its low 

 specific gravity (large flakes from the coarse veins gave a sp. gr. 

 of 2*25) is sufficient to distinguish it from molybdenite for which it 

 might excusably be mistaken in the rock, and which, according to 

 our previous ideas, might with greater likelihood be expected in this 

 association. The special tests applied confirm the determination 

 of the specific gravity and leave no doubt as to the identity of the 

 mineral. 



Although much more abundant in the felspar-rock associated with 

 the elseolite-syenite, zircons are sometimes found in the same section 

 as elaeolite. Treatment of the crushed rock with dilute acid invari- 

 ably gives rise to noticeable effervescence, due to the calcite which 

 is seen occasionally as small granular crystals in sections of the 

 rock. 



Chemical composition of the Elaeolite-syenite. 



For the purposes of chemical analysis, a large specimen of the 

 prevalent type — the grey, even-grained rock of Sivamalai — was 

 selected (No. 11,460). The specific gravity of the specimen was 

 2 '593« The graphite was separated from the crushed rock by 

 means of Sonstadt's solution, washed, and, after treatment with 

 hydrofluoric acid to remove all silicates still adhering to the scales, 

 dried and weighed. Although the layer of scales made a good 

 "show" when floating on the Sonstadt's solution, the graphite 

 amounted when weighed to 0*58 per cent, only of the rock taken. 

 The other constituents of the rock have been determined by my 



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