III.— The Makum Field * 



The Makum coal-bearing area stretches along the outermost range, 



or rather outermost spurs, of the hills to the south 

 Boundaries, &c. n p ■ ^ t 



and east of the small fortified post of that name. 



The measures extend down to the base of the hills, and the northern 

 surface boundary of the field is therefore the edge of the alluvium : I 

 have already explained that the main fault, by which the Sub-Himalayan 

 are brought against the coal rocks, in all probability passes not far from 

 the foot of the hills. To the south of the measures we have rocks belonging 

 to the Tipam and Disang groups. My observations are not sufiiciently 

 numerous to enable me to color these, but the limit of the India-ink- 

 tinted area is probably not widely difierent from the southern boundary 

 of the field, to the east of the Namdang at least. 



The most easterly point to which the measures have been traced 

 is south-east of Kerimgaon, but they very probably extend as far as 

 the end of the ridge, where they would be cut off by the southern trend 

 of the alluvium. In the opposite direction coal has been found in the 

 Dirak nadi, but between that point and the Disang I have no observa- 

 tions. The western termination of the field therefore, and the geological 

 lines between that and the Taurauk garden are conjectural. 



The extreme points at which coal has been actually found, then, are 

 thirteen miles apart, but the probable total length of the field is some 

 miles more. All the most valuable seams yet known or worked are 

 included in the area between the Tirap and Namdang. West of the 

 latter stream but httle is known of the field. 



As is commonly the case, the hills conform in their longitudinal 

 direction with the strike of the rocks, but they do not form a continuous 



* Twenty-four miles east-north-east of Makum lies the Namchik coal-field (Mem. Geol. 

 Surv. Ind,, Vol. IV, page 399), and beyond that again, the Namrup. These are, however, 

 beyond the limits assigned to our exploration. 

 ( 304 ) 



