56 On the Geology of Thayet Myo. [No. 9, new series. 



old capital of Ava, nothing "but tertiary rocks appear in the river 

 valley, the main or prevalent strike of which corresponds with the 

 direction of the river valley, that existing upon the broken edge 

 of these beds is another series of sandstones and conglomerates, 

 principally sandy, a few calcareous, though without any true lime- 

 stone. Fossil bones are found in some of these beds, which (the 

 beds) form the natter expansions between and amongst the ranges 

 and hills of the older tertiaries and the plateaus on their low 

 summits. 



The Geological age of the older rocks is said to be pretty well 

 established as being of the Eocene period, the age of the more 

 recent group is not determined, but supposed to be identical with 

 that of the Sriwalik group of India. 



The corresponding epoch amongst European strata is not de- 

 termined. 



Metamorphic and Crystalline rocks begin to appear near Ava." 



Such is Mr. Oldham's opinion, and which I have expressed often 

 indeed almost entirely in his own words. 



He does not appear to have extended his researches into the 

 interior of the country — his observations apply entirely to the 

 immediate vicinity of the river. 



My own limited observations in this neighbourhood, made with 

 an almost equally limited knowledge of the subject, have fully 

 enabled me to verify Mr. Oldham's observations to a certain extent. 



The valley in which Thayet Myo is situated comprises an un- 

 dulating plateau about 160 (?) feet above the sea, and from 40 to 

 80 above the lowest level of the river, rising to the southward and 

 westward into low ranges of rolling hills, backed by higher and 

 more broken and precipitous ridges ; the undulating plains are 

 composed of clays and river sands, with gravel composed of small 

 rolled quartzose pebbles. Many of the lowest hills are, apparently, 

 entirely alluvial ; and in the next higher series (especially to the 

 southward) sandstones occur, many abounding in marine shells. 

 The highest hills to the southward furnish a compact limestone 

 with shales and a vein of coal, which I have not yet visited, but 

 which was inspected by Professor Oldham. Specimens of the 

 shelly rock and of the limestone, are amongst those forwarded, 

 and are labelled respectively v. vi. and vii. 



