JABAL QAIYARAH. 21 



Petroleum. 



Natural Seepages. — I located four areas where seepages occur, but 

 there may be others. 



The first is marked on the |-inch map as " Naphtha Spring," 

 and consists of three separate patches of bitumen and tarry oil, 

 the two upper being connected by a stream of bitumen. It is 

 impossible to make an estimate approaching any degree of certainty 

 regarding the thickness and amount of bitumen here and elsewhere, 

 owing to our ignorance of the irregularities in -the floor on which it 

 lies. It is of course a mere surface deposit supplied by numerous 

 small vents up which the tar producing it oozes ; the supply therefore 

 is an easily exhaustible one and will be replaced only after a consi- 

 derable lapse of time. The uppermost patch of the area in ques- 

 tion is irregular in shape, but covers something like 100,000 square 

 feet. An assumption of 6 inches average thickness would give 50,000 

 cubic feet as the amount present. The middle patch is larger and 

 the richest of the three, being partly covered by a lake of water. It 

 is an oval area of about 400,000 square feet ; the thickness is over 

 one foot in places, but taking one foot as the average, the amount 

 present would be 400,000 cubic feet. The lowest patch is not much 

 larger and probably very thin. We may assume it to contain 50,000 

 cubic feet. The total for the combined area thus becomes 

 500,000 cubic feet, but it might well be double this or considerably 

 less. There are numerous small vents up which an inflammable 

 gas, consisting largely of hydrogen sulphide, issues, together with a 

 thick black tarry oil in process of being transformed into bitumen ; 

 there is every grade, in fact, from a viscous tarry oil, through plastic 

 tar or bitumen, to solid brittle asphalt. Where water accompanies 

 the oil, a pool is often formed in which sulphur is deposited, derived 

 from hydrogen sulphide, of which a strong odour pervades the area. 

 The oil from which the bitumen is produced is, in all probability, 

 derived from some seeping petroliferous limestone beneath the 

 alluvium. Some of the bitumen is mixed with earth, and that of 

 the stream connecting the two upper patches contains many 

 pebbles. The solid brittle asphalt is a form of " manjak ;" it 

 resembles in appearance a lignitic coal, but an application of heat 

 will demonstrate the difference, the bitumen melting and emitting 

 the characteristic odour. 



The second bituminous area is close to the oil wells, and covers 

 an area perhaps a little larger than the first. The bitumen is thicker 



