1847.] Notes, chief y Geological, from Goaty to lhjdrahail. 483 



the bed or vein runs east by south, and in many places is amethys- 

 tine. 



In a vein of quartz near Palmacul the purple colour of the amethyst 

 is more decided ; and, at this place, I detected, in combination with 

 oxydulated iron ore, oxide of manganese, which I have little doubt im- 

 parts this beautiful tinge to the quartz. 



At Shemsabad, about 19 miles south from Hydrabad, another vein 

 of similar quarz occurs. 



Hydrabad. — Hydrabad is situated in the lowest part of a shallow 

 flat valley, bounded by irregular granite rocks which rarely rise more 

 than 400 feet above its general level. According to the barometric 

 measurements of the Trigonometric survey, Hydrabad is 1672 ft. above 

 the level of the sea ; Secunderabad 1837 ft. ; and the granite rock of 

 Moel Ally 2017 ft. The Mussy river flows easterly through this valley ; 

 and, by a transverse break through the north and south ridge of Bho- 

 nageer, about 18 miles to the eastward, to the Kistnah which it joins 

 at Wujerabad, about 47 miles west of Amrawutty. 



The plains around Hydrabad are often crowded with tors, logging 

 stones, and globular masses of granite, which Broignart, on the autli ri- 

 ty of De Luc, has pronounced to be boulders ; but which are, without 

 doubt in situ, as I have stated in a former paper on supposed boulder 

 formations in South India. 



The prevailing colour of the granite is reddish, owing to that of the 

 felspar, which predominates almost to the exclusion of quartz. — The 

 latter mineral is not wanting in the granite ; but, from some unknown 

 cause in nature's laboratory, has been segregated in large veins and beds, 

 in stead of being diffused in grains throughout the substance of the 

 rock. These veins, or beds, are still more amethystine than those of 

 Shemsabad, Palmacul, and Nagumpully. Mr. Malcolmson is of opi- 

 nion that the crystallized specimens found near the European barracks 

 are fit for the purposes of jewellery. Another amethystine vein occurs, 

 according to Christie, near the British native cavalry lines. Mr. Mal- 

 colmson has found it at Bekonurpett, about 60 miles north of Hydra- 

 bad, and I have traced it 46 miles westerly to Sedashipett ; — and 47 

 miles southerly to the vicinity of Nagumpully, It occurs often at 

 Hydrabad in hexagonal pyramidal prisms filling cavities in quart* 

 Voysey mentions their occurrence at Pitlan and Gh&zipettah. 



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