PAftT 2.] 
Theobald: Avialgroup hi Western Prome. 
U 
other, and that a local change in the direction of the beds has occurred, as his account reveals, 
circumstantially enough, the characteristic beds of the upper axials, whilst to the north these 
beds are replaced by shales of the lower group. A great deal of disturbance here occurs, 
resulting no doubt from the sharp bend and dislocation as regards its general bearing which 
the range has here undergone, but the mineral character of the rocks sufficiently indicate 
their general relations. On the south side, my colleague records, ‘shales, and a bed of 
argillaceous impure limestone,’ also ‘fine grained speckly white, and green, rock,’ and 
on the summit a porpkyritic or altered grit. On the ascent from the north by the Hlowa 
stream, we find none of these beds, wliicb, however, are seen in the Hlowa, lower down where 
my section is taken, but in their place at the point where we quit the stream bed, indurated 
shales, dark and harsh, such as mark the lower group. Higher up the ascent, softer shales are 
passed over, and at the highest point gained by me, a sort of ridge running down from and in 
the line of strike of the northern extremity of the hill, indurated grits not very well 
characterised. There was throughout these beds a somewhat notable scarcity of quartz 
veins, which, in such a focus of disturbance, I should have expected to find more developed. 
My colleague found serpentine in profusion, hut on the Hlowa spur there was none except¬ 
ing a very insignificant patch, like a dying out vein, on the summit. No trace of serpentine 
is seen in the Hlowa where the ascent commences, so that no considerable development 
of this rock occurs on the northern flanks of the hill, how common soever to the south; and 
this distribution of the serpentine tallies with many observations elsewhere, that the serpen¬ 
tine seems to affect a certain geological horizon, namely, that of the upper axials, but 
occupying a low position in them. It would convey an erroneous view to describe Shnedoung 
as the culmination of the line of serpentine outbursts running up from the south- 
south-east, since, waiving the remark that Shnedoung is not a serpentine outburst at 
all, I would observe that though Shnedoung may be described as a somewhat abnormal 
culminating peak of the Arakan range, yet it, from that very fact, does not lie within 
the ‘ line of serpentine outbursts’ properly so called, which generally occur within the 
outer ranges. Serpentine occurs in Shuedoung, and this is the only instance yet known to 
me of that rock occurring on the actual watershed of the range, the line of serpentine out¬ 
bursts usually traversing the outer hills. This deviation from its usual position in the 
hills seems accounted for in part by the fact before alluded to, that it seems to follow not so 
much a geographical zone of country as a certain geological horizon. This horizon, a low 
one in the upper axials, very exceptionally crosses Shuedoung; the main range more usually 
being solely composed of beds far lower in the series; hence, the presence of serpentine on 
Shuedoung is not at variance with its relations elsewhere to the surrounding rocks, though 
not on the ‘line of serpentine outbursts,’ (if we generalize these phenomena,) the general 
strike of which line corresponds with the general strike of the adjoining beds. 
In strong contrast with the Hlowa section is that seen along the lino of the Arakan 
road. The breadth of the axial group at Shuedoung is barely seven miles, and most of the 
beds on this line belong to the upper division of the group. At Thabie Sukan on the Arakan 
road, the breadth of the group is over 20 miles, of which not a fifth belongs to the upper 
division. Here then, we might expect a fine section of the lower group, but the value of this 
section is inversely in proportion to the length of ground it covers, and we see great com¬ 
plexity of dip and undulations of strata without the instructive section displayed in the 
Hlowa. In addition to which must be added the absence of any fossiliferous bed or marked 
mineral group in those lower axials to enable us to divide or classify them. 
I will here describe the mode of occurrence of the serpentine and its relation to 
the rocks I am now treating of. Serpentine, though widely distributed, nowhere occurs in 
patches of very large extent, if we perhaps except the Bidoung hill. It occurs in 
two ways, which may be conveniently considered separately (though perhaps the main 
