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 ^ften in the form of a rock, but of gravel 
mingled with the soil, or^ immediately beneath it. In the Ticinity 
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 
diatrict ; still containing the pipe, or vein-like formation. 
From Trichinopoly in a south and south-westerly direction the 
granite is porphyritic and contains at Verr.llimalli 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 
ccnsiderable 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 crystal,?, axinite, calcspar, chlorite, ripidolite, octahe- 
dral and specular iron, prehnite, chlorite porphyry, polyolite, schorl, 
albite, pyrope, garnet, aquamarine, nigrin, rutile, zeusite, 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- 
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