148 EANIGANJ COAL FIELD. [CHAP. VIII. 



little trap Kill of Muktochandi appear to abound more in trap than 

 more distant localities. Also the great prevalence of the traps in one 

 particular bed of sandstone is noteworthy, but it is probably due to the 

 circumstance of that bed being more easily permeable than others, and 

 of all the dykes being merely branches and ramifications of one great 

 dyke. The principal reasons for supposing these dykes to be of a dif- 

 ferent age from those which occur in the higher beds of the field, are, 

 1st, the very much larger amount of trap permeating the Lower Damuda 

 beds ;* and, 2nd, the circumstance that these horizontal dykes, and these 

 alone, appear to be thrown by faults, especially by that near Etiapora. 

 They are also thrown by two small faults North of Churalia, and by 

 another North of Madanpur. This may, possibly, be due simply to 

 the permeable bed being thrown, and to the trap of subsequent age, 

 selecting that bed, although dislocated, wherever it occurs, much as 

 coal at all heights in the Lower Damudas appears to be penetrated in 

 preference to any other rock ; but this is less probable than the theory 

 of the horizontal traps being of prior age to the faults, and perhaps of 

 older date than the ironstone shales and Eaniganj series, the very few 

 instances of horizontal dykes in the latter being easily explicable by 

 supposing that the planes of stratification proved, in a few instances, 

 to be the principal lines of weakness. It is easy to conceive that in a 

 country already disturbed many more cracks would occur through 

 which trap could be forced than in a district where the rocks had not 

 undergone dislocation, and that, in the latter instance, the weakest lines 

 might be the planes of stratification, and the more easily yielding beds 

 of the series, so that, judged by this test, there is a probability of hori- 

 zontal dykes preceding the upheaval of the 

 country, while vertical dykes are of latter origin. 

 Taken altogether, the whole circumstances show it to be probable that 



* This mi°ht be due, however, to their being lower and nearer the sources of the trap 

 outburst. 



