183S] 



some other portions of Mysore. 



&1 



some portions undergoing rapid decomposition or resisting it altogether. 

 MaTiy small granite rocks, much exposed to the influence of the weadier, 

 exhibit on their surfaces fissares both perpendicular and h-^'rizontal, 

 dividing them into small cubic masses, showing distinctly on a small 

 s-ale the mode of decomposition and separation. It raav be remarked, 

 that even the earth from the decomposed rock, when again in some 

 measure by the influence of the sun consolidated into a sort of hardened 

 baked earth, exhibits similar fissures. 



Oxidation or oxygenation is another process by v/hicli the earth's 

 surface in India is undergoing a great change. In my paper on the 

 lateritic formation this was entered into at some length. To hyper- 

 ox^'dation and decomposition are owing the lateritic, lithomargic and 

 in-ermed'ate formations. The lateritic formation is of two kinds — one 

 arising from the hyper-oxydation aid deco^nposrltion of a rock in 

 sit'i, and the other, from the decompose 1 miteriaU being afterwards 

 carried by water to a distance, forming a species of detritai laterite. 

 Ov^er the country in every direction, bui chieii ' in the neighbour- 

 hood of the cantonment, deep water-coiiraes or na labi exist, fovned 

 apparently in the following manner, and prevail Avhere the soil is 

 of a red demi-lirhomargic character. During the very hot season, 

 the sun acts so powerfully as to produce fissures and cracks all 

 over the ground, and during the rains the ^vater rushing along 

 passes down into these fissures, and Urge mass^es of earth give way, 

 forming in time these nullahs or water-courses, which generally termi- 

 nate in tanks. Tanks abound all over Mysore and are extremely dirty 

 and mu Idy, and contain a great deal of fine soil, carried thither from the 

 neighboiu-ing fields. The decomposition of rocky eminences into soil, 

 and the delivery of this into the valleys by the rush of water, must tend 

 to establish a more level state of the country. 



Near many of these tanks, or where tanks have once existed, the 

 kankar deposit is .often found. Between Mundium and Madoor, on 

 the high road to Seringapatam, there is a very extensive vallev, v/here 

 kankar is seen accompanied by the black cotton soil ; anl close to the 

 Mundium tank, in the dry season when the water is low, an impure 

 carbonate of soda and muriate of soda cover the ground like hoarfrost, 

 and sm-all calcareous nodules the size of marbles are interaiixed v/ith it. 

 A very interesting question now intrudes itself, viz. how is this kunkar 

 formed? and next to the laterite formation, is the most important with 

 respect to Indian geo^.ogv. 



Kunkar, so universally distrihuted over India, is considered to be a 

 species of calcareous tufa, divided into that of old formation, and that 



