Records of the Geological Survey of India. 
38 
[VOL. IV. 
of the upper divisions of the axials, which is better defined than the other by the mineral 
peculiarities and appearance of some of its beds. 
The section commences in what I have termed the ‘ lower axials,’ an arbitrary division, 
but useful in dealing with so vast a group. Those lower beds are entirely unfossiliferous 
as far as my knowledge extends, excepting perhaps obscure carbonaceous markings, or what 
may be annelid tracks, in some of the shales; at the same time, however, I cannot but 
think that they may yield some organic remains when more closely studied, and perhaps 
their lower beds brought to light, for at present I am ignorant of what constitutes the base 
of this group. They consist of shales and sandstones devoid of anj' marked character or 
distinctive beds and usually more or less harsh and indurated. The shales are mostly dark, 
grey, harsh, and meagre and comminuted or splintery from the pressure they have been 
subjected to; and it is along lines of crushing and faults, brine springs seem to rise 
accompanied often by an increased amount of induration of the beds in the neighbour¬ 
hood. I cannot offer any estimate of the thickness of this division, but as it is nowhere cut 
through on any of the heavy sections in the Arakan range, its thickness must surpass 
that of the upper division, so that between 4,000 and 5,000 feet may be provisionally 
adopted. 
The bed, or rather group of beds, which I have made the base of the upper division of 
the axials, has the advantage of affording what few fossils have hitherto been noticed in 
them, and of containing a limestone which serves over a great stretch of country as an 
unfailing indication of a particular horizon, whereby we are greatly aided in determining 
the relations of other beds also. Many other beds of this division likewise are very well- 
marked lithologically, so that where the limestone is not seen, we are still able to recognize 
the upper axials from some of these beds. Such, for instance, arc the white speckled grits 
and pale or creamy sub-poreellanous grits and conglomerates, which form a strong contrast 
to any rocks either below them or in the upper or mimnmlitie group against which they 
occur. At the base of the upper gi-oup (just below the mouth of the Tliayet stream in the 
Illowa section) lies a considerable bed of dark shales, massive and arenaceous, characterised 
by a CanUla (?) which occurs in it rather plentifully, not unfrecprently both valves being 
united. A few small and not well preserved gastropoda also occur, but the prevailing and 
characteristic fossil is the Cardita ; a little above this occurs the limestone above referred to. 
It is here a rubbly rock mingled with conglomerate and shale, and forming a sort of com¬ 
posite bed, part limestone and part conglomerate and shale. From this spot (Illowa stream) 
1 extracted the first Eehinoderm, and here I could find no other specimens; elsewhere, 
however, where the limestone was better developed, the species was not rare. Where well- 
developed this limestone is a homogeneous fine-grained rock, with a COnchoidal fracture, and 
usually of some pale, or dark grey, or bluish, hue. In some spots (as south of tNhttoung in 
feeders of the Thannee Cheung) it occurs of various shades of pink and yellow, and 1 have noticed 
it converted into a coarsely crystalline white marble. In the Illowa section I only noticed one 
bed of this rock, but to the south several minor beds seem to be developed about this horizon, 
whilst the bed in question itself assumes more important proportions.* This limestone can 
be traced at intervals along the outer or eastern edge of the group as far as it has been 
examined. Commencing near the frontier, loose blocks occur in the stream near Kondaingzu, 
though I did not detect the outcrop. It is again met with near the Makton about one 
* After the experience of the axial group acquired during the past season's work, 1 think there is little doubt 
that the Gwa limestone and associated conglomerate aud much of the other limestone towards the southern extremity 
of the range will prove identical with this bed. This will be interesting, though its occurrence on the western slopes 
of the range materially diminishes the probability of our perfecting our knowledge of the lower portion of the group, 
as it would seem to indicate that the whule range forms a sort of huge anticlinal in its ensemble, und that the base 
of this group is nowhere exposed. 
