80 
Records of the Geological Survey of India. 
[VOL. V. 
In 186J, Mr. W. T. Hanford, who was then entrusted with the survey of Pegu, expressed 
an opinion, founded on the examination of the Bassein district, that the altered, or “ Hill 
rocks” as he termed them from their being confined to the hilly region wherein the Arakan 
range here becomes merged, were ns likely as not altered Nummulitic strata, notwithstanding 
the gene al difference in character between these “Hill-rocks” and the unaltered Nummulitics 
met with in the. plains and outer hills; though this view could not be corroborated by fossil 
evidence, as no fossils had then been detected in these “Hill-rocks.” 
A few years later I visited a portion of the ground surveyed by Mr. Blanford; the 
result being that I found myself unable cordially to assent to the above view of Mr. Blanford, 
and preferred to allow the point to remain an open one in the hope of some evidence of a 
more positive kind regarding the relation of the altered and unaltered rocks of Pegu being 
forthcoming in time elsewhere. About this time, my colleague, Mr. F. Feddeu, who was 
then working with me in Pegu, discovered some dark shales containing Foraminifera, (Oyer- 
culina) in a small stream, on the western side of the Arakan range, falling into the Gwa river, 
and this, with one more recently discovered, which I shall notice presently, is the only 
instance with which I am acquainted of fossils having been detected well within the area of 
the “Ilill-rocks.”* The isolated occurrence, however, of a few fossils, even the most charac¬ 
teristic, at a single spot would not have been conclusive as regarded the age of the group 
constituting the great mass of the Arakan hills; and little or no progress was therefore made 
towards the solution of the question of identity or not of the altered and unaltered rocks 
of the Arakan range up to the time of my writing my remarks on the axial group in the 
Records of 1871. When, therefore, I commenced work on the frontier in the season of 1869-70 
among the “ Axials ” as restricted by me, which are here so well displayed, and in such 
contrast to the Nummulitic group of the plains, I recognised, as I thought, a confirmation of 
the view to which I had always inclined—namely, the distinctness, geologically speaking, of 
the altered and unaltered rocks which had proved so puzzling in Bassein—and in commencing 
to follow up south the boundary of the Axial group and the Nummulitics, I not unreason¬ 
ably supposed that I was holding the clue to the true relations of the rocks in Bassein. At 
first of course all went satisfactorily enough, the nature of the ground considered, for I was 
dealing with a veritable geological boundary; but I had not got well out of thcProme district 
when I began to feel less satisfied with my work. It may he remembered that I described 
the upper or typical Axials as resting on a series of shales and sandstones which possessed 
much of the general aspect of the Hill-rocks met with to the south ; and I somewhat hastily, 
though with a great show of probability, concluded that they belonged to the same group, 
and that the fault, which, as I believed, brought in the upper Axials against the nummulitic 
strata in Prome, continued on and brought up the lower Axials in like manner to the south. 
By the time, however, 1 had reached the confines of the Bassein district, I became convinced 
that the boundary I was then following was illusory, that is, not a geological one, but merely 
one dividing the altered from the unaltered side of the same group, and which was becoming 
more and more vague towards tbo south, where, as Mr. Blanford had originally remarked, 
no separation was possible between these often dissimilar hut really geologically identical 
groups. Although I am now convinced in my own mind of the correctness of the view 
originally put forward by Mr. Blauford, I deemed it highly desirable, if possible, to procure 
some corroborative evidence. I had, it is true, failed to detect any fossils in any limestone 
I had yet examined within the area of the Hill-rocks; and this, coupled with the fact of 
nnmmulites being plentiful in many places among the unaltered beds, had much tended to 
strengthen my doubts of the view I was at length forced to adopt, but I determined to visit 
one spot where Mr. Blanford has marked limestone on the Pyennea Ckoung, ten miles west 
* The Banmi limestone contains corals and other fossils, but in a state that renders it doubtful if they can ; 
be satisfactorily made out, 
