1836.] 



Neelgherries and Koondahs. 



277 



tion of the rock, forming a stratum below the vegetable soil, and over- 

 laying the decomposed rock (No. 127). The only difference here is 

 that the lithomargic, or clayey, state is rarely seen, the whole substance 

 of the rock being changed into a dry, friable, rough substance, some- 

 what similar to the second stage in the Neelgherries. Another differ- 

 ence in the rocks of this plateau, is the greater frequency of granite 

 than in those of the Neelgherries (No. 12S). Besides, the decomposed 

 rock itself is of a different nature to the other; since it has the appear- 

 ance of being stratified, and, in its second stage of decomposition, is 

 more rough, is full of cavities, and bristled with sharp points, harsh to 

 the touch ; while that of the Neelgherries, in the same stage of de- 

 composition, is tolerably compact, and is not very scabrous, at least not 

 in the interior of the decomposed rock. 



In more than one place thick beds of black soil underlay the vege- 

 table mould, on the declivities of hills, and always in the low 

 valleys. Five or six miles from the eastern ghaut, we come to a round 

 backed hill, all formed of the lateritic iron ore, precisely similar to 

 that in other localities on these hills (No. 129). In many parts of this 

 hill the iron ore is compact and blistered on the surface, and in such 

 pieces the passage from compact, solid, hard, glimmering haematite, 

 into cavernous, perforated stone, perfectly resembling the most cha- 

 racteristic species of laterite, is seen in the clearest manner possible 

 (No. 130). 



Descending this hill we come to a valley, which, on account of its 

 great length, is called Long Valley, The greater number of blocks 

 jutting above the soil (at this side of the Koondahs the hills have the 

 same rounded appearance as those of the Neelgherries), on both 

 sides of the valley, are schistous diorite, mixed with many others 

 which are granitic, composed of the three usual minerals (No. 131). 

 As we approach the western end of the long valley, trap, either in 

 dykes, or as an overlaying rock, is seen passing through, or lying on, 

 the granitic rock just described (No. 132), besides immense beds of 

 pegmatite, into which the granitic rock occasionally passes (No. 133), 

 and, at the west end of the valley, the granite becomes of a fine texture 

 (No. 134). But, notwithstanding this change in the predominating 

 rock, the hornblende slate and rock are still occasionally seen, form- 

 ing a hill here and there, such as near the end of the valley, at the 

 place where the waters part on account of the change of level in the 

 country ; the diagram (PI. 7. fig. 2.) shews the face of a hill, nearly 

 vertical, completely naked, in which the stratification of the rock com- 

 posing it is very apparent, even at a distance, the strata inclined and 

 dipping "W. This mass of rock is split by five or six different fissures, 

 and at different angles to the seams, without these last being in the 

 least displaced \ and so also a thick quartz vein, which traverses the 



