54 HUGHES. — KARANPURA COAL-FIELDS. 



TalcJdr. — The Talchir flora is too imperfect to yield very satis- 

 factory results, but the stratigraphieal unity between the Damudas 

 and Talchirs tends to show that these two series are not widely separated 

 in geological time. 



Trap dyhes and intrusions. — Observations upon the trappean intru- 

 sions of the Jherria, the Bokaro, and the Karanpiira areas, suggest no 

 modification of the views expressed by Mr. Blanford in his report upon 

 the Raniganj field. 



This trap is younger than either the Talchir, Damuda or Lower 

 Panchet period, but I know of no instance in the Western Damuda 

 fields of intrusions into the Upper Panchet group. A noticeable fact 

 also is the decrease in the number of trap dykes from east to west. As 

 regards the geological age of these intrusions, I can do no better than 

 quote Mr. Blanford^s words — ^ there appears good reason for sup- 

 ^ posing that these intrusions may have been contemporaneous with 

 ' the great volcanic outbursts, of which evidence exists in the E/ajmahal 

 ' hills.^ 



^ No evidence of later volcanic action is known to exist in any 

 ^part of Bengal. The circumstance of scarcely any disturbance 

 ^having taken place at a more recent period is in itself strongly in 

 ' favor of the belief that the trap dykes of the Damuda country are 

 'not newer than the lava> flows of the E-ajmahal hills, for had volcanic 

 ' action taken place, it would probably have . been either preceded or 

 ' accompanied by disturbance. If, therefore, it be conceded that the 

 ' age of the trap dykes is not newer than that of the E-ajmahal rocks, 

 ' the period during which they might have been formed is reduced to 

 ' a comparatively small range.^ 



And the balance of probabilities appears to be in favor of those 



dykes being of Rajmahal age. 

 ( 338 ) 



