THE KOTAH DUN. 3 1 



THE KOTAH DUN. 



The Kotah dun is about fourteen miles long, stretching in a direc- 

 tion N. W. and S. E., and lying to the east of Ra'mnagar. The plains 

 at the foot of the dun are about 1,250 ft. above the level of the 

 sea ; whilst the dun as a whole may be regarded as a plateau, which 

 has been elevated 750 ft. above the plains, and become crumpled as 

 to its strata along its south-west border. The south-east portion 

 of that border is merely an escarpment lower than the dun itself, 

 whilst towards the N. W. it rises to the insignificant height of 300ft. 

 above the dun, forming a low range of hills separating the latter from 

 the plains (see sections I, II, and III). On the north-east and east the 

 dun is bounded by a series of spurs, running out from the main range 

 of the Lower Himalaya. Towards the north-west, near the Kosi R., 

 the dun comes to an end by the fusion of these spurs with the low 

 bordering hills. The eastern portion of the dun is more or less 

 cultivated, bright patches of green fields and small villages being 

 scattered for some distance round about the deserted buildings of the 

 Dechauri Iron Works. On the other side of the Dabka R., villages 

 cease in the dun proper, and reserved forest takes their place. The 

 Sub-Himalayan zone, however, is continued some way north of the 

 dun, and is bounded by the usual reversed fault between the Nahan 

 sandstone and the Himalayan slates. This divisional line will, in 

 future, be called the main boundary fault, as named by Mr. Medlicott. 

 It is remarkable for its constancy over the whole area treated of in 

 this memoir, in which area it is always the northern limit of the 

 Sub-Himalayan rocks, and the southern limit of the Himalayan slates, 

 &c. The portion coloured on the map as Nahan sandstone, between 

 the north edge of the dun and this main boundary, presents the ordi- 

 nary characteristics of the Nahan rocks elsewhere, so far as its petro- 

 logy goes, save that there is a strong band of brown earthy hematite 

 ij miles east of Dechauri, as already mentioned. These Nahan beds 

 all dip N. E. or N. N. E., with a few ocal exceptions, at pretty 

 uniform angles of between 40 and 6o°. This position of dipping 



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