ECONOMICS : COAL. 



75 



There are some instances of partial horizontal intrusion, and one 

 clear case is seen in the left bank of the Johilla river about a mile 

 north of Chichara. At Harha on the Son there is another example, and 

 here the upper sandstone with which it is in contact is hardened, thus 

 showing that it is not a contemporaneous lava flow. 



As a rule very little contact action appears to have taken place along 

 lines of intrusion : two instances may be mentioned, one between Mahroi 

 and Kannabahara west of the town of Sohagpur, and another near the 

 junction of the Rajghata and the Kunuk, in which the varying steps 

 of alteration effected by trap are most clearly exhibited. 



The first one was pointed out by Lala Hira Lai, where sandstone 

 has been changed not only into quartzite, but also into a highly crystal- 

 line rock resembling gneiss and granite. The belt of metamorphic 

 action is about 30 yards wide, and the trap is seen intruded in greater 

 or less quantities. 



In the Rajghata noticed by myself, I was at first of opinion that 

 I had met with an inlier of metamorphic rocks, but on closer investi- 

 gation it was apparent that the case was similar to that near Kannaba- 

 hara, and I was able to select specimens illustrating the various stages 

 of alteration from sedimentary sandstone to a rock which was quite 

 undistinguishable in the hand from ordinary granite. 



These instances of metamorphism are interesting owing to their 

 rarity, as in no other coal-field have I observed the same phenomena. 



CHAPTER III. 

 ECONOMIC. 



SECTION XVII. — COAL. 



I have previously drawn attention to the fact of there being in the 

 Appendix; a list of all the places at which outcrops of coal bave been 

 found in the various fields described in this memoir. I propose reducing 



( 211 ) 



