CHAPTER VI. 



CEOLOQICA.L rOEMATIOX.* 



Mt acquaintance with the science of Geology, is so slight, 

 that I have little information to give on tliis head. 'J'he 

 formation of the whole range is decidedly primitive, consist- 

 ing, almost wholly, of sienite. Numerous nodules of a 

 species of conglomerate, approaching to what is known, on 

 the Malabar coast, as laterite, or soap-stone, are found in the 

 vicinity of Ootacamund, and Kotergherry ; and in several 

 spots, betwixt the latter place and Coonoor, there are indica- 

 tions of large beds of this substance. My lamented friend 

 Dr. Christie, pointed out to me several considerable beds of a 

 whitish earth, which is used for white-washing, and which he 

 considered, to be decomposed felspar, nearly approaching to 

 the famous porcelain earth of Limoges. Quartz, in a state 

 of considerable purity, but partially decomposed, is also found 

 in great quantity, in detached blocks, near the Koondah 

 Ghat, and below Billycull. 



The sienite, composing the basis of most of the j-ocks, is of 

 a very hard description, and, but for the difficulty of working 



* ]?or the fullest information on the G-eological formation of the lulls, 

 generally, see Capt. Ouehterlony's Memoir, and the several other 

 Memoirs and reports noticed in the list of publications, which concludes 

 the appendix.. — Ed. 



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