MEMOIRS 



OF THE 



GEOLOGICAL SURVEY OF INDIA. 



On the COAL-FIELDS of the NagI Hills lorcUnng the Lakhimpuk, and 

 SibsIgae Districts, Assam, hy F. R. Mallet, f.g.s., Geological 

 Survey of India, 



CONTENTS. 



Paqe. 



I. — Introduction ... ... ... ... ... 1 



History of coal and petroleum discoveries in Upper Assam ... 3 



II. — Geneeal Geological Notes ... ... ... 14 



Crystalline rocks ... ... ... ... 14 



Cretaceous group ... ... ... •••17 



Disang group ... ... ... ... 18 



Coal measures ... ... ... ... 21 



' Tipam group ... .» ... ... 28 



Dihing group ... ... ... ... 30 



III. — The Makum FIELD ... ... ... ... 36 



IV. — The Jaipfe field ... ... ... ... 46 



V. — The Naziea FIELD ... ... ... ... 60 



VI. — The Janji field ... ... ... ... 75 



YII. — The Disai field ... ... ... ... 76 



VIII. — Economic Geology ... ... ... ... 78 



Coal ... ... ... ... 78 



Petroleum ... ... ... ... 88 



Iron ... ... ... ... 91 



Alum Shales .. ... ... ... 93 



Limestone » ... ... ... 93 



In a country like Assam, where railways are as yet unknown, and 

 roads available for wheeled traffic can hardly be said to exist, but where 

 there are innumerable streams, some navigable throughout the year, and 

 others for a greater or less portion of it, communication is carried on 



perforce almost entirely by water, 



( 269 ) 



Memoirs of the Geological Survey of India, Vol. XII, Art. 2. 



