Memoir on the Geology of the 



[Oct. 



and striking similitude of the name under which the natives (at least in 

 Hindoostani) call the Avalanche hill, that is Beejlee-ka-pnhar, the 

 mountain of the lightnings ; what a coincidence with the Acroceraunian 

 mountains of Enirus ! 



Descending a mile along the banks of the Koondah river, we join the 

 new road, following which for a little while, I turned to the left, to 

 examine the high ridge which faces the Avalanche bungalow. This 

 chain, called by the English chamois hill, on account of the numerous 

 wild goats found in its jungles, and by the natives Himigala, has 

 its origin in the group of the Avalanche hills, and, striking east- 

 wardly, runs about five or six miles, and ends in a very abrupt 

 precipice. The foot of this hill is not more than two or three 

 miles from the bungalow in a straight line. Its foot, facing the Ava- 

 lanche, is washed by a small river, the protruding rocks in the bed of 

 which are granite (No. 120) composed of felspar, golden mica and a 

 little smoky quartz. It is a fine grained rock, of a greyish black colour 

 on account of the dark hue of the quartz. Many of the masses pro- 

 jecting above the soil on the lowest parts of the hill, close to the rivulet, 

 are also the same rock, but of a coarser grain (No. 121). 



Half way up the hill are three large basaltic blocks, implanted in the 

 soil, the fracture of which is glimmering, on account of the numerous 

 needle-shaped crystals of augite entering into its composition (No. 122). 

 A little higher up is a ledge of hornblende slate, placed horizontally, 

 being the continuation of those which form the precipitous termina- 

 tion, to the east of the range. This slate is very characteristic, being 

 composed only of felspar, in small quantities, and of hornblende, 

 without any admixture of either mica or garnets (No. 123). 



Close to the jungle, near the summit of the hill, there is a basaltic 

 dyke cutting, nearly in a perpendicular direction, the horizontal strata 

 of this side of the hill, and, at the junction of the two rocks, they mix 

 together, in such an intimate manner, that the line of demarcation is 

 hardly distinguishable (No. 124). 



The stratification of this rock is seen clearly, not only in the preci- 

 pitous face (south), but also at the summit, where the immense tabular 

 masses lie quite horizontally one above the other. At the top of this 

 hill is a thick bed of magnetic iron ore, running east and west (No. 125). 

 There were also scattered here and there on the soil, geodic pieces of 

 bog iron ore (No. 126). 



From the Eastern Koondah, or Avalanche, Ghaut, to the Western, or 

 Malabar, Ghaut.— From the gorge above the Avalanche, proceeding 

 westwards, that is, from the eastern to the western ghaut, we see in the 

 sections for the roads the usual geological phenomenon, so often met 

 with on the Neelgherries, the detritus, resulting from the decomposi- 



