hughes: KURHURBARf COAL FIELD. 31 



VII. — Trap Dykes. 

 Trap dykes occur in great frequency, and, of course, will have impair- 

 ed the coal through which they pass. With the exception of two, which 

 are micaceous traps, the others are diorites and compact felspathic traps. 

 They appear to be of one age, and the direction which they pursue 

 seems no evidence of prior or subsequent injection. 



There are altogether 15 dykes. Many more will undoubtedly be 

 met with in the workings ; and of those seen at the surface, ramifica- 

 tions will probably occur in the coal. 

 Classified there are : — • 



Dioritic traps ... ... 4 



Compact felspattic traps ... 9 three of whicli are obscure. 



Micaceous traps ... ... 2 one obscure. 



Enumerating them from the east westwards. 



1. /.— *Course nearly nortb and soutb. It crosses the small tributary of tbe 



Durdurwa flowing from tbe Equitable Coal Compay's pit. Tbe seam 

 affected by it will be tbe 14 feet Moblicbuan seam. 



2. /. — Course somewbat north of east. It occurs north of Moblicbuan and south 



of the Durdurwa, Tbe coal in tbe Kuldiha mines will be affected. 

 3./! — Course irregular. It crosses tbe small stream in which tbe outcrop of 

 the third seam at Passarabbia is seen, then beads for the tank west of 

 the railway bungalows. This will affect the bottom and middle seams 

 at Passarabbia. 



4. f. — Course nearly due east and west. It is seen on tbe north side of tbe 



Durdurwa not far from tbe bridge. It affects the same seams as tbe 

 preceding dyke. 



5. f, — Course approximately east and west. It may be distinguished as tho 



Jogitand dyke, as it passes close to that village. Its average thickness 

 is about 3 feet. 



* The letters indicate the type of trap. cZ=dioritic trap. /=felspathic trap. w=mica- 

 eeous trap. 



( 239 ) 



