W6 Dr Christie on the Meteorology^ Geology^ Sfc. 



Quartz veins are very common in the granite. They are 

 sometimes so small as to be capable of being exhibited in hand 

 specimens. Sometimes they are of such a magnitude as to form 

 ranges of hills, which may be recognized at a great distance by 

 their white colour. These hills appear to have originated from 

 the indestructible nature of the quartz having enabled it to 

 withstand the attacks of the weather ; while the more perishable 

 granite was worn down all around it. There are two conspicu- 

 ous ridges of quartz which appear to have been formed in this 

 way, in the vicinity of Hydrabad. . One is near the British na- 

 tive cavalry lines ; the other is near the town of Shumsabad. 

 Drusy cavities, lined with very beautiful amethysts and rock- 

 crystals, are sometimes found in these hills. The granite, in the 

 vicinity of these veins, often passes gradually into the quartz, by 

 losing its other two ingredients. 



Trap is very common throughout the granite tract of India, 

 It is found both in veins and in extensive ov^Tlying masses. 



The veins which traverse the granite, present two distinct 

 kinds of trap. One .is precisely similar to the most common 

 I^ind of the secondary or overlying trap, viz. a greenstone of a 

 perishable nature, and having a concentric lamellar structure. 

 It therefore most probably belongs to that formation. The 

 other is more compact, has a rhomboidal structure, occurs ge- 

 nerally in smaller veins, and is much more durable. 



Large accumulations of granitic debris are met with all over 

 the granite tracts of India. In many places this debris has so 

 completely consolidated, simply by means of the aggregation 

 exerted between its particles, as to form a hard rock *. This 

 rock, in some instances, exhibits an obscure schistose structure. 



Granite is not generally employed as a building stone in In- 

 dia, on account of its great expence ; but large slabs of it are 

 sometimes brought into the bazaars for sale by the Wudrahs -f*, 

 and are used for paving the floors of the verandahs in the bet- 



" Kirwan mentions an instance of an ariificial accumulation of granite 

 sand having so completely consolidated, by means of a simple aggregation 

 between its particles, as to form a rock so hard as to be impenetrable by wa- 

 ter. 



t A vagrant class of people, somewhat resembling the gypsies. 



