Memoir on the Geology of t h\ 



[Oct. 



and between which and another the present rivulet runs, whose waters 

 having undermined the stratum (which might have overlaid thick beds 

 of clay, the result of the decomposed rock) the weight of the superin- 

 cumbent mass, together with the almost vertical position of the stratum, 

 made it slip — hurling rock, soil and jungle into the valley below, leaving 

 a deep ravine, bounded to the north by a mural precipice of undecom- 

 posed rock, some hundred feet high, and to the south by the remainder 

 of the declivity, which is seen undisturbed in its place, having the same 

 altitude as the opposite boundary. 



Sinkings in the soil about this place do not appear to be a rare occur- 

 rence; since in the declivity of the hill on which I stood, there was one 

 of a semi-circular form, many hundred feet in circumference, and of 

 which the affaissement of the soil was hardly a foot ; and I could descry 

 a larger one, on the northern declivity of the Avalanche hill, where, the 

 slope of the ground being rather steep, the depth of the sinking was 

 greater at the upper than at the lower part. 



Returning to the road I began ascending the ghaut. The view from 

 all points of this ascent is really grand. I do not recollect having seen 

 anywhere such a wild, yet magnificent, spectacle as the ravine formed 

 by the two hills— the one of the Avalanche chain, the other one of the 

 eastern range of the Koondahs. The thick impervious jungle, extending 

 its whole length, occupies also the lower half of the steep declivity of 

 both the hills, and is then succeeded by the usual carpet-like covering 

 of dense turf, which extends to the very pinnacles of their prodigious 

 altitudes. 



Before I had an opportunity of visiting the Koondahs, judging by their 

 outlines as seen from Ootacamund, I surmised that their sharp peaked 

 profile indicated granite as their formation rock. But, on a nearer 

 approach, it is seen that this appearance is fallacious ; since this eastern 

 range of the Koondahs has in reality the same rounded form as the other 

 hills in the Neelgherry group, so as to be as easy of access, even on 

 horseback. 



While ascending this pass, at every turn of the road a most striking 

 and superb coup oVoriI presents itself — the nearly vertical side of the 

 Avalanche hill, with its precipitous battlement-like summit— the enor- 

 mous prismatic masses, three or four in number, bursting, as it were, 

 through the turf-covered soil of the steep declivity of the hill ; one of 

 which, in particular, looks like a huge martello-tower stuck to the 

 nearly vertical side of the mountain— while the magnificent ravine to 

 the left completes the striking view before us. This assemblage of wild 

 and grand objects, cannot but produce sensations of wonder and admi- 

 ration. 



On arriving at the gorge of the pass, of course the view, becoming 

 more expanded and enlarged, has a superior degree of beauty, partica- 



