968 On Porcelain Clay found at Mangalore, Sj-c. []No. 120. 



low pits in the diluvium, and remarking the similarity between this 

 deposit, and those in which gold is found in other parts of the world, 

 I made enquiries of the natives respecting it, and ascertained that they 

 procured gold here by washing in the rainy season. Having seen no 

 geological account of the gold works in this part of India, I am not aware 

 whether this metal has yet been found in its original matrix, or whe- 

 ther it is wholly derived from this loose transported deposit, or dilu- 

 vium, as geologists call it. The latter forms a succession of low rounded 

 hills, which are intersected by streams, and are every year partially 

 worn down by the rains, which is perhaps the origin of the river gold 

 of these districts. 



The Neilgherry hills are entirely composed of primitive rocks, con- 

 sisting principally of granite, gneiss, a large quantity of earthy felspar, 

 quartz, and a peculiar rock, which I would name corundum rock, from 

 its having that mineral as one of its principal ingredients. I have met 

 with nothing analogous to it in Europe, and it occurs in great abun- 

 dance ; many of the hills being entirely composed of it. 



Some interesting questions connected with the parallelism and ele- 

 vation of strata, and other branches of theoretical geology may derive 

 elucidation from a more minute survey of the Neilgherries, and the 

 neighbouring country ; but as these are not suited to a report of this 

 nature, I must reserve them for the memoirs I hope to be enabled 

 to publish at some future period on the geology of India. 



The climate and agricultural features of the Neilgherries are more 

 interesting and more worthy of attention than their geology. These 

 hills, rising in the middle of the torrid zone, to the height of nearly 

 9,000 feet, present every variety of climate, from that of the plains 

 of India to that of England. The climate of their higher parts resem- 

 bles that of the great intertropical cities of South America,* which 

 have become the centres of civilization in the new world ; but is 

 superior in one point of view, being never subject to those sudden 

 changes and cold piercing winds, which are occasioned by the vicinity 

 of lofty mountains, some of which are capped with snow. The mean 

 temperature of Ootacamund is rather more than that of London, 



* Quito is about 9,000 feet above the level of the sea ; Santa Fe de Bogota, 8,000 

 feet ; Mexico about 7,400 ; and Caraccas nearly 3,000 feet. Although the latter place 

 has been called an earthly paradise, its climate is changeable and unhealthy. 



