Chap. XXIT. ROIL— CLIMATE. 359 



to swell the great river Cauvery, by its tributaries the Moyaar 

 and Bowany; the Moyaar descending from the hills by a 

 fine waterfall at Neddiwuttum, on the northern slope ; and 

 tlie Bowany flowing down between the Koondahs and Xeil- 

 gherries to the south. The soil of the plateau is very rich, 

 being formed by the decomposition of basaltic and horn- 

 blende rocks, mixed Mith the clayey products of the granite, 

 and much decomposed vegetable matter. The latter consists 

 of the gi-ass killed down to the roots by the frost, washed 

 in by the succeeding rains, and mixed with the subsoil, 

 increasing its richness and depth season after season. The 

 richest laud is on the lower slopes, where there are accu- 

 mulations of soU washed from the hills above : ^ and there 

 are extensive deposits of peat in the valleys, which afford 

 supplies of fuel. The cliief defect in the soil is the absence 

 of lime. 



The temperature and amount of humidity vary according 

 to the locality. At Ootacamund, 7300 feet above the sea, 

 the means of the thermometer range from 42° to 68°, while 

 in the two other lower and warmer stations of Coonoor and 

 Kotergherry, about 6000 feet above the sea, the range is 

 fi'om 52° to 71°. The annual rainfall at Ootacamund is 

 sixty inches, at Coonoor fifty-five inches, and at Kotergherry 

 fifty inches. During the south-west monsoon, from May to 

 September, the rain comes down in torrents at Sispara, 

 and in the western parts of the Keilgherries, but then- force 

 is somewhat exhausted before reachiQg Ootacammid, in the 

 centre of the plateau. At that station the rainfall, during 

 the south-west monsoon, is about thirty-fom- inches ; and the 

 range of Dodabetta, which rises up like a wall, immediately 

 to the eastward of Ootacamund, almost entirely screens the 

 eastern part of the hills from the rains of the south-west raon- 



2 Reporl of Captaiii J. Ouchterlony, Sup'rintt^udcit <>/ the Ncilgherrij Survey 

 i 1848. 



