Dec. 1861.] 



Geology of the Neilgherries. 



229 



No remains of animals of extinct species, as far as I can collect, 

 have as yet been discovered. 



The Hill streams disengage from the banks of their channels 

 small fragments of the primary rocks, and deposit them in their 

 beds, they are usually angular fragments, being too near their 

 gangues to be yet rounded by attrition. In the sands of the Oota- 

 camund lake are small pebbles of quartz, which if possessed of a 

 deeper shade of green would be called Prase. 



I must not overlook the deposit of a soft unctuous scarlet fer- 

 ruginous mud, from the waters of some rills in a valley between 

 Ootacamund, and Chinna-Coonoor. Where the waters have par- 

 tially stagnated, they are encrusted with a chatoyant film ; the 

 taste is usually that appertaining to chalybeate springs. I shall 



take occasion in the sequel to refer more particularly to those 

 waters. 



Diluvium. — There is every reason to suppose that the deluge 

 took these Hills within its scope. 



That this flood swept over the mountains in a torrent from the 

 Eastward, is manifest in the position of the Erratic blocks and 

 Boulders, which lie generally along the western slopes and bases 

 of the eminences. It is also confirmed in the arrangement of the 

 Diluvial stratum, in the presence of conglomerates cemented by 

 an indurated clay of aqueous origin, and, what seems singular to 

 assert, in the greater luxuriance of vegetation on the Western 

 faces of the Hills. The boulders and blocks consist of granites, 

 Eurites, Syenites, and greenstones, chiefly resting on the red soil 

 into which some of them have sunk partially owing to their great 

 weight ; many of them have been rounded by attrition during their 

 head-long flights while suspended in the torrent. Occasionally 

 they are seen in groups, sometimes wholly detached. 



Between the vegetable soil, and the red earth which had pro- 

 bably commenced decomposing before the Deluge, lies the dilu- 

 vial detritus, consisting of fragments of various rocks here met 

 with, sometimes rounded into pebbles. The detritus in many cases 

 may be seen to have fallen into rents in the substratum. This de- 

 posit cannot be classed as alluvial, for no casual overflowing of 

 streams or ordinary rains could have deposited it where it prevails, 



