ECONOMIC RESOURCES. 73 



That these rocks do extend throughout in this way is for several 

 reasons doubtful ; but whether they do or not is not of much importance 

 from an economic point of view, as the coal could not be profitably 

 extracted from under the great superincumbent mass of trap which 

 forms the hills. It is certain, however, that there are particular seams 

 which might be worked for considerable distances underneath the ed«-es 

 of the trap. 



In some of the early accounts of these hills it is stated that the 



Coal not injured by coal nas been vei T mucn injured by the basaltic 



rap * 'trap ; more recent examination has shewn that this 



is not the case. I have not met with a single instance where the coal 



shewed any trace of such effects as are commonly to be seen in the 



vicinity of the intrusive dykes in the Damuda valley coal-fields. 



It has been stated on a previous page that the Damuda rocks of the 

 northern third of the hills appear to be of a different age and are pro- 

 Prabably two groups hahl Y younger than are those of the remaining 

 of coal-measures. two-thirds. And it is, moreover, evident that the 



thick seams of the northern part of the area do not occur in the south 

 unless the Hurnsingha seam, which is high in the Brahmini valley section, 

 should perchance correspond to one of the northern seams. 



Much uncertainty must on this account attach to any estimate which 



Imperfection of data ^ ** ° ffered ° f the tot&1 am0Unt ° f COal available 

 for estimate of total in the whole area. Neglecting the verv numerous 



amount of coal available. _ J 



thm seams which could not possibly be worked 



with profit, an average of 5 feet would certainly not be an under-esti- 

 mate of the thickness throughout. This would give 5 x 70 x 600,000 

 = 210,000,000 as the amount of coal in tons, which could be got from 

 the exposed area without following the seams under the younger rocks. 

 As this, however, could be done to some extent in large mines, the total 

 available amount would be still greater. In this somewhat rough calcu- 

 lation I have not taken into account the amount of coal which has been 

 k ( 227 ) 



