92 NOETLING: PETROLEUM IN BURMA. 



A glance at the boring registers shows how almost hopeless 

 it is to introduce order into this confused mass of details. The chief 

 difficulty is due to the similarity of the strata met with. There is 

 no lithological difference between two samples of clay, the one coming 

 from near the surface, the other from, say, 1,000 feet depth, and the 

 same remark applies to the arenaceous beds. No fossils having 

 been found in any of the beds, we are therefore unable to identify 

 the strata found in different wells. The task is rendered the more 

 difficult, because certain features, which will be dealt with in a 

 subsequent chapter, indicate a very peculiar structure of the Yenang- 

 young oil field. If we further consider that the vague terms which 

 the drillers used to designate the beds, such as " shale," " slate " 

 and " clay," may in one case all mean one and the same argillaceous 

 bed, while in other cases they really represent lithological differences, 

 it is obvious that a fairly accurate identification of the strata found at 

 different places by different men and at different times, recorded in 

 varying terms, is almost hopeless. After carefully comparing the 

 above records one feature was, however, very conspicuous ; imme- 

 diately above the sand which chiefly produces the oil there is a bed 

 of clunchy clay which seems of particular tenacity. 



The fact was also established that within certain limits this bed 

 occupies a remarkably constant position above sea level. Thus an 

 important horizon has been established, the beds above and below 

 which can be considered separately. I must mention, however, that 

 in some cases the identification of this bed is not absolutely certain, 

 and the boring records may therefore be interpreted in a wav 

 different from the one I have suggested in the sections constructed 

 on the strength of the boring registers. I do not think, however, that 

 this will materially affect the theoretical conclusions deduced 

 therefrom. 



It is extremely difficult to say whether the beds thus distinguished, 

 and succeeding each other vertically, represent true geological 

 horizons or not. In fact there is sufficient evidence to believe that 



( 138 ) 



