YENANGYOUNG. 89 



that the structure of the Yenangyoung oil field is in the shape of 

 a dome-like anticlinal, but before attempting to explain the forma- 

 tion of this feature, it will be useful to describe the sections as 

 observed on the surface and then to discuss the sections from the 

 deep borings. 



B. — The Superficial sections. 

 In order to get at a fair idea of the transverse structure of the 

 Yenangyoung oil field, I have constructed five cross sections, one 

 occupying about the middle and two to the north and south of it. 

 It was fortunate that the chief direction of the natural drainage 

 runs across the anticlinal arch, and thus the main ravines afforded 

 an exceedingly good opportunity for the study of the sequence of 

 the strata and their structural features. It will be seen that the 

 Irawadi series and Yenangyoung stage are chiefly exposed, while 

 the topmost part of the Prome stage is only seen along a short 

 distance in three of the sections. Although not much can be said 

 about the sections which has not already been stated before, it 

 will be useful to explain each with a few words. 



Section No. 7 (Pl. XIV) from kyunbodoung tothepinchoung. 



This section exhibits the series of strata observed north of the 

 Yenangyoung oil field, at that particular part where the zone of 

 Hippotherium antilopinum is preserved in the centre of the anticlinal' 

 Beginning at the western boundary line, the beds of the Yenang- 

 young stage extend along a horizontal distance of about 3,500 feet 

 towards the east, and represent a thickness of about 2,200 feet, 

 dipping at about 25 to west, then follows the zone of Hippotherium 

 antilopinum, with a thickness of about 25 feet, and below it, but 

 very badly exposed, are the top beds of the Yenangyoung stage. 

 Passing the centre of the anticlinal the zone is again met with, 

 but now it dips towards east, followed by the Irawadi series, dipping 

 at about 25 . 



( 135 ) 



