232 Geoloyy of the Neilgherries. [No. 12, new series. 



Crossing this Hill shortly after my arrival from the low country, 

 I was struck by the appearance of the stones^dispersed upon it, and 

 on examination found they were pieces of Siliceous Schist, a rock, 

 I apprehend, that has hitherto eluded the observation of the Geo- 

 logists who have made the Neilgherries the field of their research. 

 I discovered the vein of Schist appearing at the surface, half 

 way down the Eastern talus of the mountain, and subsequently 

 tracing it to the North East side I found a section two hundred feet 

 broad associated with Trap, and forming a flight of natural steps 

 which lead from the peak to the ridge below. At a more recent 

 period, following the direction and dip of the vein, which are iden- 

 tical, I found it again displaying itself more to the Southward, 

 and a long way down the declivity. Pursuing this line I encoun- 

 tered pieces of it in a bank near General King's house in Oota- 

 camund ; and a little further on it occurs in great abundance, 

 though in fragments, in the bank of a morass, where it assumes 

 an argillaceous character. Notwithstanding that no direct evi- 

 dence of the vein traversing the Cantonment exists, I am induced 

 to believe these fragments are outlying pieces from it, because 

 they maintain the line of strike with but little deviation. The 

 dip of the Schist, as observed by me at Snowdon, is about 40 de- 

 grees to the South West. 



The South West slope of the peak is conformable to this angle. 

 The Hill itself is a mass of Syenite, varying from the red rock of 

 Egypt to what has been called Greenstone Syenite, but is really 

 Green S3'enite, through the inconstant proportions of the Horn- 

 blende it contains, the changing colors of its minerals, and an al- 

 teration in the size of their crystals. Northward the Schist ter- 

 minates at the Trap stairs, but an extension of the latter rock has 

 occasioned those along the ridge to affect the Schistose character 

 in an inconsiderable degree. On the whole I compute I have 

 traced the Schist to a distance of two miles. 



This interesting and remarkable vein consists of the following 

 materials. 



(a.) Siliceous Schist passing into, 

 (b<) Lydian Stone, passing into, 

 (c.) Siliceous Jasper passing into, 



