1837.] 



Geology of the Deccan. 



359 



of the ghats. The heaps are from twenty to seventy feet in diameter, 

 and the same in height : when composed of rocky masses without 

 small stones, blocks of three or four feet in diameter and with a dis- 

 position to determinate forms, are piled upon each other, constituting 

 rude pillars. In certain parts of the country from fifty to sixty of 

 these heaps are seen within the area of a couple of square miles, and 

 it excites surprise that the intermediate ground is destitute of stones. 



Sheets of Rock. — Mention must not he omitted of the constant re- 

 currence of sheets of rock of considerable extent at the surface and 

 totally destitute of soil : this is particularly the case in the Mawals, 

 or hilly tracts along the ghats. They abound with narrow vertical 

 veins of quartz and chalcedony. When of sufficient thickness, the 

 vein splits in the centre parallel to the surface of its walls, the in- 

 terior being drusy with quartz crystals : the walls consist of layers of 

 chalcedony, cachalong, hornstone, and semi-opal. These veins sup- 

 ply the majority of the siliceous minerals so. abundantly strewed over 

 Bukhun. 



The localities where the sheets of rocks particularly struck me were 

 Lakungaon, on the plain of Joonur, and generally in the valley of the 

 Goreh river ; at Kothool, Pergunneh Kurdeh ; at Kheir and Raseen ; 

 in the hill fort of Hurreechundurghur ; most markedly between 

 Kooldurrun and Pairgaon on the Beema river. At Aklapoor, on the 

 Mool river, they w T ere very extensive ; and at Angur, Mohol, Kurjut, 

 and Patkool. Generally in the eastern and south-eastern parts of my 

 tract, much decomposing amygdaloid is found at the surface of the low 

 table-lands or terraces, which, in favourable monsoons, is equal to the 

 support of Jowaree* ; but a small deficiency in the rains occasions the 

 destruction of the crop. 



Structure and Mineral Composition of the Trap Rocks.— The struc- 

 ture and mineral composition of the trap rocks in Dukhun vary exceed- 

 ingly in short distances, even in the same stratum ; nevertheless, the 

 predominant character does not disappear, although the basalt in a 

 continuous bed may pass several times from close-grained, compact, 

 and almost black, to gray, amygdaloidal, and external decomposing. 

 The same observation applies to the amygdaloids. A variety of com- 

 pact basalt,of an intense green colour, is susceptible of a brilliant polish, 

 and rivals the celebrated Egyptian kind. It is of great weight and 

 remarkable hardness : the natives use it to work into idols for their 



* Andropogon Sorghum, 



