Burma : A Handbook of Practical Information - Khamkoo

GEOLOGY-ROCKS 49
of newer alluvium, older alluvium, and silicified wood and
bones of mammals in sands and gravels of the Pliocene
age. The Pegu Yoma consists entirely of the Miocene
group, with beds of later Tertiary age, chiefly sandstone
and shale. The Arakan Yoma, and the spurs to eastward
and westward of the main range, are chiefly of earlier
Tertiary age, resting on Cretaceous and Triassic beds,
which rise to the surface on the western face of the range.
The Carboniferous limestone, and its associated beds,
together with the Mergui group, appear to run up the
line of the Salween. The Mergui group consists of
highly metamorphosed rocks resting upon granite, and
showing every variety, from gneiss and raica slate to hard
silicious slates, occasionally chloritic, and to black and
earthy, but micaceous and glossy, slates. Numerous veins
of granite run through these. Above this comes a great
accumulation of beds of pseudo-porphyritic rock, which
form the higher grounds of all the outer ranges in the
south, but ai-e less strongly represented towards the north.
The total thickness cannot be less than 9000 feet. To
the northward there are beds of hard sandstone, covered
b}' a series of grey, shaly beds, and above this a 200-feet
layer of fine, soft sandstone, on which rests the hard and
thick limestone so largely developed near Moulmein.
This has a thickness apparently of about 1000 feet or
more, and extends northward, in large hills and ranges,
into Karen-ni and the Shan States. The abrupt cliff's, full
of caves, characteristic of the formation, are very noticeable
near Mcing Nai (Mone), and northward in the same
latitude. The same formation is found east Of the Salween,
in Kengma, Kokang, Chenkang, and probably far
northward. It seems to belong to the Carboniferous
series, and to be identical, in part at least, with the
limestone found in the Mergui Archipelago. Until the
fossils are better known it is impossible to say whether
the Burma series exactly corresponds to the Carboniferous
beds of the Himalayas and the Punjab. They are certainly
of the same approximate age. The occurrence of
marine fossiliferous rocks of the Carboniferous period at
the two extremities of the extra-peninsular area of British
India, and the complete absence of any iTiarine Palaeozoic