OETAILKI) DKSORIPTIONS OF THE RESPECTIVE COALFIELDS 15 
In the same vear (^aptain Vetch^ found a " very thin seam of 
remarkably fine, but singularly heavy coal " on the Dakaru stream, 
some 6 or 7 miles above the confluence with the Buri Suti and some 
considerable distance east of Dalton's find. He mentions a rumour 
of coal occurring on the Sisi river. Although without certainty, 
it is probable that these finds may be referred to the Upper Ter- 
tiary sandstones of Mallet,^ La Touche'^ and J. M. Maclaren* 
in which the writers referred to record the frequent occurrence 
of lignite bands and semi-carbonized wood. J. M. Maclaren, how- 
ever, in referring to specimens of " true coal " brought to him from 
the Subansiri river, mentions a circumstantial account of what might 
possibly be a burning coal-outcrop, such as has altered to coke 
much of the outcrop coal at Margherita in the Makum field. 
Daphla and Aka hills. — Damuda rocks were discovered in 1875 by 
Colonel Godwin Austen^ in the section in the Dikrang river. He records 
the finding of a much splintered and crushed coal seam which was from 
5 to 6 feet thick and dipped 75° to E. S. E. In character the 
coal resembles that from the Darjiling foot-hills, and it is 
unlikely to be of future economic value. 
In 1883-84 Mr. La Touche® encountered a continuation of the 
same belt of rocks in the Aka hills to the north of Tezpur, 
The rocks are well exposed in the valley of theBorholi river, where 
at least three coal seams were found, the thickest of which 
measured 18 inches. Their economic value was considered to 
be negligible. 
The Naga, Patkai and Singpho hills. — ^The coal-bearing rocks of 
these ranges were described by Mallet " in 1874-5, whilst the infor- 
mation has been recently brought up to date by J. M. Maclaren,^ 
R. R. Simpson,^ H. H. Hayden, and E. H. Pascoe." They are 
best known in the Makum area, but they stretch for 40 miles 
1 Cal. Jour. Nat. Hist., VII, p. 368 (184()). 
2 jfe^.^ Q_ s_ XII, 297 (1876). 
' Bee, 0. S. J., XVIII, 122 (1885). 
* Rec, 0. S. I., XXXI, p. 191 (1904). 
^ Journ. As. Soc. Beng., XLIV, p. 37 (1875). 
» Eec, G. S. I., XVIII, pp, 121-124 (1885). 
' Mem., 0. 8. I., XII, p. 269-363 (1876). 
8 Rec, O. S. I., XXXI, pp.188-191 (1904). 
" Rec, G. 8. I., XXXIV, pt. 4, pp. 199-239 (1906). 
" Rec, G. 8. I., XL, pt. 4, pp. 283-319 (1910). 
" Rec, Q. a. I., XLI, pt. 3, pp. 214-216 (1911). 
