132 NOETLING: PETROLEUM IN BURMA. 



of 133 feet, without its lower limit being touched. It has mosft 

 probably been identified in Nos. 1 and 2, but here the drill did not go 

 so deep as in No. 6; it seems that it contained only a very small 

 quantity of oil. 



The occurrence of oil calls for no further remarks, as it has been 

 already mentioned that it seems subject to periodical fluctuations 

 like that of Yenangyoung. The only remarkable feature is the com- 

 paratively high pressure prevailing in some of the oil sands, which int 

 one instance at least has forced up the petroleum from over 500 feet. 



Section 3. — Stratigraphical Features. 

 A.— 'The superficial sections. 



As already stated the ravines, which cut through the hill range at 

 almost right angles, generally afford very good cross sections, but at 

 the present only those in the Yanaung-choung ravine have been 

 examined in detail. From the sections on PI. XVI, it will be 

 seen that next to the river, the beds of the Irawadi series are 

 exposed along a zone, whose breadth varies very much ; it is 

 about 500 to 600 feet in this section. The strata closest to the 

 river bank stand nearly perpendicular, but a little further away, the 

 dip is eastern, but still very high and not below 70 within the 

 boundaries of the Irawadi series. The dip slowly decreases down 

 to about 40 to 45 at a distance of about 1,200 feet from the river, 

 when rather suddenly it changes to about 7 west. The strata form 

 therefore an unsymmetrical anticlinal fold the eastern side of which 

 is marked by high angles of dip, which however rapidly change from 

 about 90 to 45 towards the apex of the anticlinal, while the western 

 side is characterised by a low and very constant angle of dip. 



The remarkable topographical features of the Tangyi range are 

 therefore easily explained by its geological structure. The eastern 

 side where we see a mass of rugged low hills with steep eastern 

 slopes, is represented by the steeper side of the fold. On the 

 western side, where the angle of dip is lower, the natural slope is 

 more gentle, and the nature ol the ground therefore not so rugged. 

 ( 178 ) 



