312 . On the formation of the 



hills, conical summits are found, elevated nearly 6,000 feet 

 above the sea ; they are peculiar for being round and smooth 

 in outline, and are covered with a cellular ferruginous clay- 

 stone, which appears to be allied to what Dr. Benza has 

 called ec hcematitic iron ore" upon the Nielgherry hills. These 

 high summits are formed of hornblendic granite, which is 

 more solid and compact than the euritic granite of the 

 other parts, and the clay stone lies upon this. The clay stone 

 when pounded yields a deep red powder, in colour exactly 

 like colcathar of vitriol (peroxide of iron) and might perhaps 

 be used as a pigment. In some of the cellular cavities, there 

 is a sort of botryoidal dark coloured calcedonyj but the whole 

 has much the appearance of a volcanic product. About their 

 most elevated parts lithomargic earth occurs; but I do not 

 agree with Dr. Benza in believing, that it results from the 

 decomposition of the ferruginous claystone. 



A very singular peculiarity of these table lands is the oc- 

 currence of the springs of water, which run copiously all the 

 year round, I believe, without any diminution at any season. 



On the Shairvaroy hills, a spring of this kind is found about 

 100 feet only below the highest summit, and is of great 

 advantage in watering the plantations of coffee there. In 

 this case of course all the European theories for causes of 

 springs fail, there being no higher level from which to bring 

 the water, and although there are hydraulic principles by 

 which waters could be imagined- to be so raised, such as the 

 transmission of the pressure of one column of water by inter- 

 posed air to the top of another column, and thus multiplying 

 the pressure ; yet if these ranges of hills are formed of a mass 

 of granite, how can the fluid be transmitted unless through 

 the softer portions between the blocks, or through a vertical 

 stratification. 



It is remarkable, that the soils on these table lands are 

 always much richer, and more ferruginous than those of the 

 plains below. 



