1845.] from Pondicherry to Bey poor. 769 



garnet, (if so it is, for I have not yet had opportunity of submitting 

 it to analysis) is in general of the foliated, rhomboidal variety, and 

 with its white quartz matrix form a very beautiful rock. The quartz 

 imbedded also a mineral of a hair-brown colour in hexagonal prisms. 



The variegated appearance imparted to the limestone near the line 

 of junction by the admixture in irregular lines of red and green 

 crystals, is curious and interesting. 



These beds can be traced on the side of the rock till they disappear 

 under masses of porphyritic granite, which have slidden down from 

 above. In contract with veins of granite the garnet rock acquires a 

 glazed surface, and a disposition to split into prisms when struck with 

 a hammer. 



The felspar of the porphyritic granite is usually reddish; the mica 

 dark green, and the quartz of a light transparent grey. The two 

 latter minerals are occasionally wanting ; the felspar becomes a granu- 

 lar or compact paste, imbedding larger crystals of felspar ; in short, a 

 true porphyry. 



The country surrounding the base of this rock, which affords so 

 instructive an example of the effects of Plutonic intrusion among the 

 metamorphic schist, is bold and rocky ; and, towards Salem, the dark 

 low ridges show that hornblende schist is the prevailing rock, inter- 

 sected by low ridges of white quartz. 



Near Sankerry-droog granite and gneiss are more common ; the 

 presence of the first being clearly indicated to the traveller by the 

 bolder aspect of the country. 



The gneiss and other hypogene strata are almost every where bent 

 and contorted. The Traveller's bungalow stands on a bare surface of 

 gneiss, presenting a curious example of contortion, and the rock of 

 Sankerry-droog is a finer example of granite veins in gneiss than the 

 far famed Cape Wrath itself, figured by AlcCulloch and Lyell. 



The soil is mixed regur and red alluvial ; saltpetre is manufactured 

 in the vicinity. 



The hill fart was once a place of great strength, and originally built 

 by a Beder Poligar, it was subsequently strengthened by Hyder and 

 Tippoo, and within the last twenty years was garrisoned by the Com- 

 pany's troops. 



c * 



