418 



an area of about 2G,000 square miles, and lying between the paral- 

 lels of north latitude 16° 45' and 19° 27', and east longitude 73° 30' 

 and 75° 53'. 



The whole of this tract, whether at the level of the sea or at the 

 elevation of 4500 feet, is composed of distinctly stratified, horizontal, 

 alternating beds of basalt and amygdaloids, without the intervention 

 of the rocks of any other formation. Similar stratification and struc- 

 ture is instanced in Malwa, and in the Vindhya, Gawelghur, and 

 Chandore ranges of mountains. 



The Dukhun (the mean elevation of the valleys and table-land of 

 which is about 1800 feet above the sea) is described as rising very 

 abruptly by terraces from the country at its base : to the eastward it 

 declines by terraces ; but these being low, and occurring at long in- 

 tervals, excite little remark. On the top of the Ghauts there are 

 numerous spurs or ranges of mountains extending to the E. and S.E, 

 The valleys between them are either narrow, tortuous and fissure- 

 like, or wide and flat ; both ends being of nearly equal width. A 

 river runs through each valley, having its source at the western end. 

 The author does not think it physically possible for the present rivers 

 to have excavated any of these valleys. Those of a fissure-like 

 character might be referred to a period when the country was heaved 

 up from below the sea, if such ever took place ; but this explanation 

 would not account for the broad flat valleys margined by scarped 

 mountains, 



The author notices successively the extensive occurrence of co- 

 lumnar basalt, and instances numerous localities of basaltic pave- 

 ments of pentangular slabs; being, in fact, the terminal planes of 

 basaltic columns. He also notices singular insulated heaps of rocks 

 and stones, the loose parts of which manifest a disposition to geo- 

 metrical forms. He witnessed repeated occurrences of nodular ba- 

 salt, or basalt en boules; of stupendous escarpments} of dykes of 

 great length, in some instances crossing each other} of strata of 

 ferruginous clay under compact basalt, which, in different localities, 

 pass from friable to jasperyj the occurrence of pulverulent lime 

 in seams ; and minute nodular limestone on the surface and in the 

 banks of rivers. Crystallized lime was noticed as an imbedded 

 mineral only. He observed numerous veins of quartz and chalce- 

 dony traversing the basaltic strata, and supplying the major part of 

 the siliceous minerals abundantly strewn over the country, such as, 

 agates, jaspers, hornstones, heliotrope, semiopal, stilbite, heulandite, 

 mesotype, ichthyophthalmite, pseudomorphous quartz, &c. &c. ; and 

 he mentions the occurrence of muriate and carbonate of soda, of the 

 ores of iron which are worked into the celebrated wootz steel, and 

 of thermal springs. The author did not observe any conformation of 

 the mountains resembling the craters of extinct volcanoes, nor did he 

 find organic remains of any kind. 



The paper concludes with some general observations (limiting their 

 application to the 25th degree of north latitude) on the amazing extent 

 of the trap, laterite, nodular limestone, granite and gneiss formations 

 in the peninsula of India. From the geological papers of Capt. Dan- 



