GENERAL RELATIONS OF ROCK GROUPS. 33 



be a little higher in position than the rocks of Kamthij but still are 

 an integral part of the same group. 



We have thus the Kamthi beds hitherto looked upon as Damudas^ 

 and the Mangli beds hitherto classed as Panchets, both belonging to 

 the same group. To which of the two above-named formations are 

 they to be referred, or do they belong to neither ? 



First as regards the Damudas. The mineral character has been 

 shown to be totally different. North-west of Nagpur, in the Tawa valley, 

 north of Betiil, — north, in the Pench valley, near Chhindwara, — north- 

 east and east, in various localities from the neighbourhood of Jabalpur 

 to the Tributary Mehals of Katak, — and south, close to Chanda, 

 Damudas occur, always with precisely the same character. At Chanda 

 moreover, these Damiida beds distinctly underlie rocks precisely 

 similar to those of Kamthi, and the numerous borings which have been 

 made for the purpose of proving the extent of the coal seam, as well as 

 the survey of the country by Mr. Hughes, have shown that unconformity 

 to some extent exists between the two groups. It is true that the 

 Damudas in Chanda very possibly represent only the lower sub-division 

 or Barakar group of Bengal, and the Kamthi beds may replace the 

 higher sub-divisions, the ironstone shales and Raniganj beds, but the 

 Kamthis differ from the two last named in mineral character to even a 

 greater extent than they do from the Barakar beds. So far as mineral 

 character is concerned, therefore, it is impossible to assign the Kamthi 

 beds to the Damiida formations. 



Next as regards the Panchets.* I have very little hesitation in 

 classing the red clays of Maledi,t south of the Chanda, containing Cerato- 



* By Panchets I mean throughout this paper, except where upper Panchets are ex- 

 pressly mentioned, the beds called lower Panchets iu my report on the Raniganj coal-field. 

 I am now convinced of the fact, which I suggested in that report (Memoirs Geological 

 Survey, vol. iii, p. 30, note), that the name should be restricted to the lower division, the 

 upper division being a well distinguished group. 



•j- Memoirs, Geological Survey of India, Vol. I, p. 295. Quarterly Journal, Geological 

 Society, Vol. XVII, p. 349 j Vol. XX, pp, 117, 280. 



I ( 327 ) 



