202 GEOLOGICAL RELATIONS OF THE ROCK SYSTEMS 



than the Jurassic age assigned to these coal strata had been accumu- 

 lating. The abundance of Ceratodus teeth at Maledi, in the south o* 

 Nagpur, at once determined the horizon of those beds, as nearly, if not 

 exactly, that of the Upper Trias of Europe, while the abundance of 

 Estheria minuta* and the occurrence of the labyrinthodont Brachyops 

 at Mangali went far to fix the age of the Mangali rocks, as decidedly 

 older than Oolitic, if not truly Triassic. 



I have, however, hitherto in my remarks on this subject commonly 

 avoided any attemptf to bring into correlation beds or groups of beds 

 in other parts of India, which the Geological Survey has not visited, 

 with those in Bengal, excepting in the broadest and most general way- 

 With the experience we already have of how very little has yet been 

 learned of even the physical evidence of these rocks, I believe it to be 

 useless, if not worse than useless, to attempt any very close identifica- 

 tions of rocks, separated by a distance of some 500 miles, the inter- 

 vening country being quite unknown. I feel perfectly satisfied that 

 every portion of the series will, as facts accumulate, take its proper place 

 in the general series, and I have already said that " great as the delay 

 may be, it is safer and wiser not to hazard any erroneous conclusion by 

 hasty speculation. "J 



The Nagpur country, which will undoubtedly throw much light on 

 these rocks, must be examined by itself, and the relation of its groups 

 of strata to each other determined before they can justly be brought 

 into comparison with those in Bengal. And great as have been the 

 contributions of Messrs. Hislop and Hunter, much, very much yet 



*tJour. Geol. Soc. London, vol. xii. p. 376. 



f Vol. II., p. 334. 

 t I have for this reason avoided insisting on the confirmation of my views, which is appa- 

 rently afforded by the Ichthyolite beds at Kotah. There is very strong reason for believing 

 these to be above and separated by a veiy marked break in sequence from the " laminated 

 sandstone" or " Damuda" rocks. And if it be admitted that the Kotah beds are Liassic, it 

 will follow that the others are much older. But we know too little of the relations of these 

 rocks to insist on this conclusion. 



