182 NOETLING: PETROLEUM IN BURMA. 



I have adopted this view in my former two papers, but I must 

 confess that it never fully satisfied me, as there were many cases 

 which seemed to be opposed to this view. In the geological descrip- 

 tion I have, however, demonstrated the existence of three successive 

 oilsands, and the restriction of the two upper ones to a very limited 

 area. The wells in the ravines, therefore, most probably did not 

 touch the ist and 2nd oilsand at all, or if they did, they were not oil- 

 bearing, and the diggers had to go deeper till they reached the level 

 of the 3rd sand. It must therefore be supposed that two wells of the 

 same depth, one being situated on the plateau, the other in the 

 ravine, draw their oil from two different oilsands, following each 

 other in vertical position. Of course the natural dip of the strata 

 must not be entirely disregarded, as it is almost certain that a well 

 situated farther from the centre of the anticline will traverse the 

 strata diagonally, and thus reach a given horizon at a greater depth 

 than if constructed on the axis of the anticlinal. 



The greatest depth I recorded in well No. 411 was 317 feet from the 

 surface. It seems almost certain that this represents the maxi- 

 mum depth to which the Burmese well digger is able to go. The 

 noxious gases at that depth render any length of stay in wells 

 without artificial ventilation impossible ; but even if the Burmans 

 were to resort to this, the crude way in which they would certainly 

 carry it out would prove most ineffective. Besides the long time 

 which lapses in hauling up a man from that depth by the usual 

 Burmese method, is so considerable that it would prove very expen- 

 sive to deepen a well of over 300 feet only a couple of feet. As the 

 return is also very uncertain very few wells have reached a depth 

 beyond 300 feet, and we may take it almost for granted that 320 feet 

 is the limit to which the Burmans can go with their method of digging. 

 The practical importance of this fact is obvious, and conclusions which 

 may be drawn from it have been already dealt with in a previous 

 section. 



I found it convenient to divide the wells into five classes, accord- 

 ing to the depth which they have attained,— such a division would be 

 ( 228" ) 



