MAKUM FIELD. 43 



A quarter of a mile lower down there is another. 







Ft. In. 



Ft. 



In. 



Arenaceous shale, seen 



Grey shale 



CoaZ, dipping east 40° south at 60° ... ... 2 



Grey shale 

 Brownish shale, seen 



4. 

 2 



2 



4 





 6 





 



On the left bank of the stream, where it leaves the hills, are two 

 old coal quarries, now quite choked up. They are probably in different 

 seams. The sandstone close to the more southerly of these dips south- 

 east at 40*, and near the other east-10°-south at 15°. 



In a nalla on the hill-side south of Jaihing, a seam is visible, of 



which, however, only 1 foot is exposed. Dip east 

 S. ofJaihing. > } J r r 



20« south at 60". 

 A couple of miles above the debouchure of the Makum nadi 

 from the hills, a 3-feet seam was observed, dipping 

 Makum nadi. gouth-east at 30^ and fifty yards further on 



another is obscurely visible. 



On the right bank of the Dirak where it leaves the hills, there 

 Dirak nadi. ig a seam having the following section : — 



Ft. In, Ft. In. 

 Grey shale, seen ... ... ••• ••• 2 9 



Coal ... ... ... 3 



Grey shale, seen ... ... ... ... 3 



Dip about south-south-east at 80® ; coal soft and crushed. 



In coal-fields of limited extent, where the measures are nearly hori- 

 zontal, a useful approximation to the quantity of 



Quantity of available p ■, -i i i i t_j. • j i, ' i^' i • n 



pogj "^ fuel available may be obtamed by multiplymg the 



area by the mean thickness of the coal. But the 

 circumstances of the Upper Assam fields render this method inappli- 

 cable. In all of them the measures have a high general dip towards 

 the hills, and the seams must rapidly sink to a depth below which 

 the coal could not be profitably worked. No doubt there are local fold- 

 ings of the strata by which seams may be brought to the surface a 



( 311 ) 



