198 Notes Illustrative of the 



Investing a portion of this quartz-porphyry, were found 

 crystals of an ore which I am inclined to believe was spe- 

 cular iron ore. Its characteristics were highly metallic, 

 inclining to adamantine ; colour dark grey, nearly black ; 

 hardness between 7 and 8 ; fracture splintery ; structure lami- 

 nated ; specific gravity not numerically determined, but high ; 

 crystalline form a flat rhomboid. In the adjoining hills 

 felspar of the sienite was occasionally of a pink colour, and 

 dendritic on the surface. Transported masses of green- 

 stone, basalt, mica, and clay slate were found in the vicinity 

 of the streams, though none of these rocks were observed 

 in situ. 



The country between Palleconda and Vellore, while it 

 exhibits no variety in geological structure, is interesting 

 from the singularly wild and beautiful character of its 

 mountain scenery. On the summits of the hills the tor- 

 like masses of the sienite are grouped in the most varied 

 forms, sometimes shooting up like spires, at other times 

 strewed around like the ruins of some extensive edifice, or 

 again standing square and solid, like the massive walls and 

 donjon keep of some robber chieftain's tower. The valleys 

 are covered with similar blocks piled on each other in the 

 wildest confusion, the whole seeming to tell of mighty con- 

 vulsions, rather than of the slow and scarcely perceptible 

 operations of the agents of disintegration and decay. 



A monotonous and uninteresting plain, with but little to 

 attract the attention of the geologist, extends from Vellore 

 to Madras. The same sienite which forms the distant hills 

 underlies the whole of this plain, outcropping at several 

 points. It was met with immediately under the sand during 

 the progress of an artesian well sunk in the immediate 

 vicinity of Madras, which after passing some little distance 

 through the rock was abandoned ; and indeed it is singular 

 that considering the geological configuration of the district 



