60 
Records of the Geological Survey of India. 
[vol. VII. 
being at the same time very free from shaly partings. Near the south boundary of the field, 
along the base of the permanent rise of the main range, the coal was found in two places ; 
but here it has the disadvantage of having undergone much disturbance. In the stream a 
little to the west of the lower village of Baduri, a few yards below the Daranggiri path, the 
coal is thus seen in full force, but nearly vertical. On the same strike, within a mile of the 
Semsang, ou the path between Baduri and Janliaray, the approximate position of the seam 
is marked by large and abundant debris. 
On the evidence of these facts, it is, I think, safe to conclude that there is here a coal¬ 
field of considerable extent. The coal-measures are certainly continuous within the area 
demarcated by the localities I have mentioned, covering roughly about twelve to fifteen 
square miles ; and although the coal itself is probably not Co-extensive with the measures, 
the total quantity must be very large; and it is favorably circumstanced for mining. It lies, 
however, in the very heart of the Garo hills ; but on the most favorable line for a railway, 
through the gorge of the Semsang, should it ever be thought advisable to undertake such 
a work. The nummulitic formation with its limestone caps the high ground in the centre 
of the basin. 
The Rongrenggiri basin .—Some miles up the valley of the Semsang, to the west, there 
is another considerable basin of the coal-measure rocks, occupying the valley above and 
below the Rongrenggiri outpost for a direct distance of seven miles, from a little below 
Sarramphang Haut to below SkemshanggirL Locally it is five miles wide. I could no¬ 
where find an outcrop of the coal within this area ; but there are stratigraphical features 
(see further on) suggesting that it may exist within the basin at greater depths than the 
present surface. 
The Kalu basin .—On the Upper Kalu, north of the main gncissic range, about Chipa- 
giri, there is a small basin of the coal-measure rocks; but no trace of coal has been observed. 
Hero, too, it may possibly be found at greater depths by boring; but the field would seem to 
be shallow and closely circumscribed by the gneiss. Even if found, there would be several 
miles of difficult transit to get the coal to market. 
The main basin .—Every other observed appearance of the coal-measure rooks to the 
north of the Turn range (excepting one narrow strip in the valley at Lenkra, in the far- 
east), consists only of patches of variable extent and thickness, resting on the ridges and 
spurs of the crystalline rock, some occurring locally near the Semsang even on the crest of the 
main range. In so steeply eroded a country, these cappings of sedimentary rocks are freely 
exposed on all sides to denuding action, and the presence in quantity of any peculiar material 
could scarcely escape detection; where, too, at any time a shallow trench dowu the hill side 
across the bedding would lay bare the whole contents of the section. Yet in none of the very 
many places where I crossed the measures in this position did any symptoms of coal appear. 
With the single exception of a small patch on the north shoulder of the ridge below the 
village of Sokadam, every observed outlier of the oretaceous formation occurs within the 
basins of the Semsang and the Kalu, in the neighbourhood of the main axis of elevation; the 
whole stretch of hills for twenty miles ou the Goalpara side being, at least on the two trades 
crossed by ine, entirely formed of gneiss. The original sites at the extreme west end of the 
hills, at Olmmpagiri and Mirampara, remain as the only known cases of the seam being re¬ 
presented in a mere remnant of the measures on a low platform of gneiss. Thus, excepting in 
the very doubtful project of a railway through the Semsang gorge and the Daranggiri basin, 
and also in the unlikely possibility of still finding a detached basin within easy reach of the 
Goalpara boundary, the only prospect of a coal-supply still lies in the main basin of the 
formation, to the south of the Tura range. 
