1839] 



some other portions of Mysore. 



95 



ing nmcli iron, the colour is a ligbt rich red. A soil similar to this is to 

 be found between Mysore and Goondiepeir, and seems to arise from the 

 decomposition of chlorite slate with an admixture perhaps of hornblende 

 and oxide of iron. 



The black cotton soil occupies, according to Dr. Heyne, four-fifths 

 of the Peninsula of India, and the cause or causes which lead to 

 the formation of this soil form an interesting saljject in Indian geo- 

 logy. It was referred by Dr. Voysey to the decomposition of a 

 basaltic trap. A passage from some notes kept during a late geolo- 

 gical tour bears upon the present point. " Started for Periapatam-road 

 throQgh jungle for four or five miles — soil black, occasionally red, — After 

 this jungly tract, the road passes through a fiat country, containing a 

 good deal of black soil, having small pieces of knnkar on the surface, 

 and much impregnated with saline matter. Just before entering Peria- 

 patam there is a deep water-course, with masses of basaltic hornblende 

 lying exposed. This section shows for about three feet, the black soil 

 so prevalent over this part of the country— succeeded by a reddish yel- 

 lov'f earth, in which were rounded masses of basalt or basaltic horn, 

 blende — below this again was gneiss in a decomposing state, containing 

 veins of a calcareous substance similar to what was before described, 

 and having a vertical position.'' Here then was basaltic trap decom- 

 posing into a reddish or rather yellowish earth. How then could it 

 form the black soil which was above? lean only answer by saying, 

 that farther on at the bottom of Coorg, I found the same black soil 

 and some way up, but it changed then to red without any particular 

 change in the rock. Now having observed much kunkar for some time 

 before reaching the bottom of these hills, I asked myself the question, 

 whether this black soil did not originate from a jungly country being 

 covered for some time by water, or whether it was not the result of a 

 calcareous admixture. In many parts of the country where this soil 

 exists I have found kunkar beneath, as at Hoonsoor and Yelwall. 

 Hornblende and basalt, as before observed, are constantly seen decom- 

 posing into a reddish or yellowish earth, highly ferruginous ; and when 

 they do form into the black earth, is it from the quantity of calcareous 

 matter which we know these rocks often contain? or is it from the ad- 

 mixture of calcareous and ferruginous matter, making this far famed soil 

 to be of a calcareo-ferruginous nature. By analysis it has been found 

 io yield chiefiy lime and iron, and its very name of cotton ground, from 

 that plant flourishing in it, is in favour of its calcareous origin, for the 

 soil most favourable to the growth of cotton is that which contains a 

 very large proportion of lime. Does not this view of things reconcile 

 the apparently conflicting opinions of Voysey and Benza. Dr. Benza 



