96 NOETLING: PETROLEUM IN BURMA. 



oil field. None of these cross sections quite correspond with each 

 other. Of course a general sort of agreement may be made out, but 

 the more I have studied and compared them, the more difficult it 

 seemed to explain their unusual features. 



The most conspicuous instance is shown in section V, between wells 

 No. 19 and No. 1 1 and No. 10. In No. 19 immediately below the lowest 

 bed of the Yenangyoung stage there is a bed of sand of 130 feet in 

 thickness followed by the clay (e) ; in No. 11 immediately below the 

 same bed a stratum of clay of 201 feet in thickness has been found, 

 followed by a thin bed of sand containing petroleum below which 

 follows clay {g) ; in No. 10, there is a bed of sand of 212 feet thick- 

 ness immediately below the beds of the Yenangyoung stage separa- 

 ted from the oil-sand by a bed of 63 feet thickness of clay, noticed in 

 the two other bore holes. Now it is quite evident that such a re- 

 markable disappearance or thinning out of beds of nearly 200 

 feet in thickness within such a short distance would be rather ano- 

 malous, even if we admit that such rapid and sudden changes in 

 the lithological character of the beds do take place within the same 

 level. 



In fact the prqblem of the discrepancy of the various sections 

 puzzled me so much, that I considered it an almost hopeless task 

 to obtain a clear idea about the structural features of the oil field ; 

 I almost felt inclined to assume that serious blunders must have been 

 committed in recording the beds through which the borings were 

 made. The study of Professor Orton's ingenious paper on the 

 occurrence of petroleum in Ohio, suggested an explanation ; he 

 observed the remarkable fact that the successful wells were always 

 on the domes while the dry wells were situated in sinks or depres- 

 sions of the anticline. 1 



The idea suggested itself to classify the wells of the Kodoung 



1 Geological Survey of Ohio, vol. VI., iSSS. Do. 3rd organization, vol. I., 

 1890. The Trenton limestone as a source of petroleum and inflammable gas in Ohio 

 and Indiana, U. S. Geological Survey, Sth Annual Report. 

 ( M2 ) 



