YENANGYOUNG. Ill 



tion hardly requires any explanation. From No. 14, where the top of 

 the No. 3 oil-sand has been found at 135 feet above sea level, it 

 gradually rises towards No. 25 where it was found at 225 feet ; from 

 there it falls slightly towards the inferior well No. 37, more so towards 

 No. 42, where it reaches the level of 170 feet above sea, and now, as 

 may be supposed according to the theory, it rises again towards the 

 inferior well No. 50, where its level is 185 feet above the sea. This 

 section affords, therefore, a very good idea of the slope on either side 

 of the central ridge on which the rich wells are situated. 



The eastern side of the petroliferous trad.— In the same 

 way as the longitudinal sections were constructed on the western 

 side of the tract, a similar one might be constructed on the 

 eastern side, but unfortunately the wells are not so numerous there ; 

 and the few which do exist are separated by such long intervals, 

 that it is impossible to construct such a complete section on the 

 western side. I may, however, be allowed to quote a few instances ; 

 the rise of the surface of the 4th oil-sand from the poor well No. 52 

 towards the inferior well No. 50 has already been mentioned ; the 

 same applies to the tract from well No. 49 towards No. 53, or No. 40 

 towards No. 38. 



It would be useless to go further into details ; I think the above 

 has conclusively proved that, independently of the general structural 

 features expressed in the dome like shape of the Yenangyouno- oil 

 field, there exists a series of folds, transverse to the direction of the 

 axis of the anticline, which must have existed previous to the forma- 

 tion of the latter. It remains, therefore, only to explain the origin 

 of these folds. 



d. — The original sedimentation of the petroliferous beds. 

 In the foregoing section I have shown that the Yenangyouhg 

 oil field exhibits a very complicated structure, due to two causes; 

 viz.: — 



1. A transverse action, resulting in the creation of the anticlinal and longitudinal 

 arch. & 



2. A longitudinal action, resulting in the creation of the intersecting folds. 



( 157 ) 



