RECORDS 
OF THE 
GEOLOGICAL SURVEY OE INDIA. 
Part 2.] 1871. [May. 
The Axial group in Western Peome, British Burmah, by W. Theobald, Esq., 
Geological Survey of India. 
When examining the southern portion of the Arakan range, I applied tho term ‘axials’ 
to a group of rocks which seemed everywhere to comprise the central region or axis of the 
range, hut the relations of whieh to the newer or nummulitic group were not there very 
clearly displayed, partly from the nature of the ground and partly from the character of the 
beds which, though of great thickness, were very deficient in any salient points for arrange¬ 
ment and sub-division. In Western Prome, however, there is a great improvement in these 
respects, and the axial group is so well displayed that we obtain, not only a good insight 
into its relation with the newer group whieh adjoins it, but, from a few good sections, a 
tolerable conception of its own principal stratigraphical sub-divisions. Tho best and most 
illustrative sections are met with near the frontier, particularly in the Illowa stream, 
where an enormous thickness of beds dips with much regularity and at a high angle, the 
section comprehending beds of both the axial and nummulitic groups. 
As we go south the breadth of country covered by this group increases materially, and 
with this increase in breadth, there is a proportionate change in the arrangement of the 
beds, the high steady dip observable to the north there becoming replaced by a variable, 
and oft n extremely low, one. 
At the frontier, tbese beds are 13 miles in breadth measured from the crest of the range 
at right angles to its general strike, which breadth is diminished to 7 miles at Shuedouug, a 
remarkable hill thirteen and a half miles south-west by south from Mendoon. From this point 
the ‘ axials’ gradually expand till they attain their greatest breadth of twenty miles at Thabio 
Sukan, a bait ing place on the Aral;an road.* The relations of the axial and nummulitic groups 
are nowhere better seen than along the frontier, proceeding west from the village of 
Sangyi. The road from Sangyi to Yebile (Yua-ba-lay in map) lies over an undulating and 
in part hilly country of the ordinary character seen within tho outer ranges of hills composed 
of nummulitic strata. The forest is moderately thick and the low vallies rather well supplied 
with water, (considering that the previous rainy season had beeu very scanty, and most of 
the streams were unusually low in consequence). Prom many points along this line of road, 
the bolder character and denser forest of the main Arakan range formed a prominent and 
* It would seem to have been no fortuitous circumstance that dictated the adoption by the Burmese of the line 
along which the Padoung and Tonghoop road (Arakan road) now runs, and which is the line along which the Burmese 
formerly transported, at great cost and toil, a colossal image of brass of Gaudatna as a trophy of their prowess, 
from Arakan to their own capital. The road traverses the indurated rocks at the point where they are actually 
broadest, and where, in place of having to traverse ridges of highly inclined rocks, the road undulates over a series 
of spurs, whose ultimate origin must be looked for in the geological structure of the region. 
