290 



Memoir on the Geologij of the 



[Oct. 



After a few minutes we began our descent, and had a few more 

 glimpses of the recess, acccording as the cloudy curtain was, every 

 now and then, withdrawn. We went round the base of the peak to the 

 northern gorge at its foot, and, from this place, the vertical facade of 

 the peak is seen to great advantage. The apex of the cone appears to 

 overhang the base, and the face is rather concave. From this place I 

 could at ease contemplate and admire, without fear of giddiness, the 

 romantic scenery before us. 



From this altitude we occasionally looked towards the east at the 

 Cantonment, of which we could distinguish some of the houses, and to 

 our tents, the way to which appeared, from such a heigh!, quite easy 

 and smooth — facilis descensus — so that, instead of retracing our steps, 

 we chose to descend the side of the hill (N) a continuation of the peak. 

 Here my labours and fears began ; I never scrambled down precipices 

 so nearly perpendicular to the horizon as I was obliged to do on this 

 occasion. 



The three mountains, ascended previous to reaching the peak, are all 

 ormed of hornblende slate, abounding with garnets, of which the 

 whole of the group is formed (No. 163) ; it decomposes into a friable, 

 crumbly substance (No. 164). In the bed of the rivulet, at the foot of 

 the peak, this rock is traversed by a thin basaltic dyke. 



At the south gorge the outgoings of the decomposed hornblende 

 slate are seen, assuming the rough scabrous appearance of the lateritic 

 iron ore (No. 165), for which I took it at first, at a little distance. I 

 must repeat here that no where, on the Neelgherries or on the Koondahs, 

 have I seen the rock in such an utter state of decomposition as in this 

 group of Makoortee ; sometimes the whole thickness of a huge mass 

 being converted into friable, semi-compact rock, and the greatest number 

 of the blocks being surrounded by many feet of the decomposed rock, 

 still in situ. 



The whole of the peak is formed of a beautiful schistous diorite, 

 common in many places of the Neelgherries, and abounding with in- 

 numerable garnets. The hornblende is highly splendent, black and 

 foliated j the felspar rather scanty ("No. 166). Sometimes the horn- 

 blende is in a prismatic form, and arranged perpendicularly to the 

 seams ; in the specimens I shall forward, the stratification is very evi- 

 dent. 



In the middle of the declivity of the peak I saw hardly any basaltic 

 dykes worth mentioning; none at the summit, and an insignificant one 

 at its foot (No. 167). Is it to the absence of intruding rocks that the 

 strata of the hornblende slate owe their horizontal position? Many of 

 them are composed of pure hornblende (No. 168). 



The rocks in the northern gorge at the foot of the peak, were decom- 

 posed as in the southern, bst more extensively (No. 169), Having 



