oct. — dec. 1856.] of the Southern Division. 99 



does in other places. So also some of the syenite on the tops of 

 the mountains is found to rest upon granite. Indeed syenite is not 

 known to be an underlying rock to any extent in any part of this 

 district, but appears in blocks or rounded masses both on the 

 mountains and some parts of the plains. 



In the direction of Vellum and Poothacotta from Trichinopoly 

 the granite pierces the laterite, which covers most of the surface, 

 in a number of places where it appears either in ridges of some 

 height or in broken masses scattered over the plains, but the late- 

 rite does not appear here often in the form of a rock, but of gravel 

 mingled with the soil, or immediately beneath it. In the vicinity 

 of Vellum and from that place south through the Poothacotta and 

 Sivagunga districts, the laterite takes more the form of a glomerate 

 rock and is used for building purposes. Its appearance in some 

 places when it is forming is that of a liquid percolating the soil and 

 forming for itself small pipes, or veins which branch in different 

 directions not unlike the veins in the human system ; these multi- 

 ply and harden till the whole mass becomes thoroughly impregnat- 

 ed with iron, and by degrees formed into a hard and rich iron ore. 

 Considerable hills are formed of this substance in the Poothacotta 

 district ; still containing the pipe, or vein-like formation. 



From Trichinopoly in a south and south-westerly direction the 

 granite is porphyritic and contains at Verallimalli a vein of nodu- 

 lar greenstone imbedding granular chlorite and beautifully white 

 albite. On the road from Trichinopoly to Dindigul at Amaparthi 

 is a bed of granular limestone imbedding grains of pyroxene, of 

 considerable extent and hardness ; this is found in some cases 

 united to the granite, connected with the felspar of which, are 

 crystals of vermicutorite. At Manaparie 25 miles south-west from 

 Trichinopoly, the granite is diversified by large masses of viscid 

 quartz and quartz rock and granite ; the minerals found at this 

 place are rock crystals, axinite, calcspar, chlorite, ripidolite, octahe- 

 dral and specular iron, prehnite, chlorite porphyry, polyolite, schorl, 

 albite, pyrope, garnet, aquamarine, nigrin, rutile, zeuxite, arseniate 

 of copper, nicoline, and crystalline hornblende. 



Near Corttamperthe is an extensive bed of silicate of iron ; it 

 forms a part of four small mountains and continues in one direc- 



