Q2 SMITH : GEOLOGY OF MIKIR HILLS IN ASSAM. 



to be a continuation of the great sandstone band of Haflong and 

 the Burrail range, in the North Cachar hills, which is again con- 

 tinuous with the sandstone series of the Mikir hills, of pliocene 

 age. Much silicified wood occurs in the Tipam, as in the Mikir 

 sandstone ; and the ' arenaceous cellular limonite ' in the Tipam beds 

 must closely resemble the ' vesicular sandy haematite' common all 

 over the south Mikir hills. 



No beds corresponding to Mallett's Dihing coal-conglomerate 

 group are met with in the Mikir or North Cachar hills, where prob- 

 ably the uppermost pliocene is wanting. 



The shale and sandstone series'are seen to thicken considerably 

 southwards from the Mikir hills. A similar increase evidently 

 takes place eastwards also, resulting in greatly developed groups 

 in the Naga hills. 



The nummulitic coal-beds of the Cherra Poonjee district have com- 

 pletely died out in the Mikir nummulitic rocks, and the great seams 

 in the coal measures of Upper Assam and the Naga hills have 

 almost died out before reaching the Mikir hills from the opposite 

 side. The latter fact may be partly accounted for by the presence 

 of local marine shell-beds in the coal-bearing shale-series of the 

 Mikir hills, showing that it was to some extent a salt-water deposit. 



Economic Geology. 



The chief mineral of value in the Mikir hills appears to be 



limestone, and this unfortunately always occurs 



Limestone. at some distance from the read and railway-line. 



The stone quarried on the Nambor is used for many miles up and 



down the road, and it seems improbable that the far greater quantities 



of much purer limestone available on the Deopani, Haria Jan, and 



Jamuna rivers, will be made accessible for many years to come. 



As in many other parts of India, iron-ore is of widespread occur- 

 rence throughout the south Mikir hills. There 

 Iron * are great quantities of ferruginous sandstone 



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