YENANGiAT. I 29 



sidered as constant horizons remains more than doubtful. All we 

 may say is, that the upper Prome stage represents a very thick layer 

 of clay which is subdivided by numerous sandy beds in layers of 

 varying thickness. 



The upper beds of the Prome stage have been ascertained for 

 a depth of about 1,100 feet from the surface, which after deducting 

 those beds considered as belonging to the Yenangyoung stage 

 allows about 800 feet thickness for the upper Prome stage. It must, 

 however, be at once added that this by no means represents the 

 total thickness of the stage, which is probably much greater. In 

 fact, it is almost quite certain that the drill is still far away from the 

 base of the Prome stage. 



The occurrence of petroleum. — As in the Yenangyoung oil field 

 the petroleum is restricted to arenaceous beds, enclosed between 

 layers of impermeable clay. These sands may contain oil and 

 water together, but the oil has always been found above the water. 

 As may be seen from the boring registers the petroliferous sands 

 vary much in thickness, the thickest bed of sand being recorded in 

 well No. 66, with a thickness of 133 feet, but the quantity, of oil it. 

 contained was apparently anly very small. 



So far not less than ten distinct petroliferous sands, following each 

 other in vertical direction, have been recognised, but it seems almost 

 certain that this number by no means represents the total num- 

 ber of petroliferous sands contained in the Pegu series* All the pro- 

 babilities tend to prove that further petroliferous sands will be found 

 in greater depths, but it is quite impossible to say whether they will 

 be richer or not than those already found. Were it permissible to 

 draw any inference from the strata already known, the conclusion 

 would be, that the lower oil sands are also very poor, but such a 

 statement would be premature as only the drill will give the much 

 desired information. The six oil sands hitherto found in the wells 

 are the following :— 



1st oil sand. — This is represented by the same bed which crops 

 out in the Yenangyoung-choung, and from which oil was noticed 

 K ( 175 ) 



