GEOLOGY OF INDIA. 3 



mica-sJiist, hornblende- shist, chlorite- slate and crystalline lime-stone; on these 

 repose clay-slate, and Jlinty-slate, and towards the base we find sand-stone 

 composing the southern steps of the chain, and forming the N. E. barrier 

 of the valley of the Jumna and Ganges, by which, and the diluvial plains 

 of Upper Hindostan, this great Zone is separated from the mountain 

 ranges of the peninsula. The opposite, or southern boundary of this 

 valley, is of the same rock. Advancing to the south, we come to three 

 inferior mountain ranges, on which the peninsular table land of India 

 may be said to rest, or more properly, to which it owes its peculiar form 

 and outline. We may consider these ranges separately, as the western or 

 Malabar, the eastern or Coromandel, and the central or Vindhya. 



The principal in elevation, and most remarkable in continuity of 

 extent, is the western range, which commences in Candesh, and runs along 

 the Malabar coast, within a short distance of the sea, in an unbroken 

 chain, to Cape Comorin, excepting where it is interrupted near its 

 southern extremity, by the great chasm which opens into the valley of 

 Koimbetur. The direction of this range deviates but little from north and 

 south, bending a little eastward towards its southern extremity ; its eleva- 

 tion increases as it advances southward, the highest points being probably 

 between latitudes 10° and 15° N. where peaks of granite rise to 6000 feet 

 and upwards.* The northern extremity of this range is entirely covered 

 by part of the extensive overlying trap formation, to be more particularly 

 described hereafter ; extending, in this quarter, from the sea-shore of the 



northern 



* In Mr. Babington's paper, in the 5th volume of the Geological Society's Transactions, the 

 height of one peak, Bonasson hill, is stated to be 7000 feet above the sea, and in a recent descrip- 

 tion of the JSilgiri region, by Dr. Sniith Young, the peak of Dodapet, situated between 11° and 

 12° S. Latitude, and 76° and 77° E. Longitude, is said to rise to an elevation of 8700 feet — it is 

 to be regretted that we have no published report of heights, by actual geometrical or barometrical 

 measurements, of the principal summits of the mountain ranges of the peninsula. 



