12 PASCOE: GEOLOGICAL NOTES OX MESOPOTAMIA. 



of the pitch of the fold. This pitch is accompanied by a flattening 

 of the arch which at Fathah is very broad and gentle. 



The Jabal Makhul shows considerable asymmetry at first, dips 

 of perhaps 25° (the maximum dip is concealed beneath alluvium) 

 on the north-east being balanced by dips of G5°, 75° and 80° on the 

 south-west. Near Jabbar the asymmetry becomes less, the dip 

 measured reaching 27° on the north-east and 57° on the south-west. 

 Across Ain Dibs we have about 25° average maximum dip on the- 

 north-east against 40° on the south-west, the latter flank steepening 

 rather suddenly towards the base of the range. Figures for Makhul 

 must be accepted as approximate only, the river on one side and 

 the alluvium on the other masking the maximum dip. As a whole 

 the crest is broad and rounded in both ranges ; in longitudinal section 

 it is also curved. 



The river has pierced the range at a weak spot where the crest has 

 sunk to the small low dome between the two crest-minima, and 

 where the direction of the fold somewhat abruptly changes from 

 62° W. of N.— 62° E. of S. to nearly due.N.W.— S.E. ; dip-faulting 

 may have assisted the river in this. That this gap dated at least 

 from Pleistocene times, is, I think, shown by the presence in its 

 neighbourhood of the conglomerate of that age. 



An interesting feature of this and other areas is the " choked " 

 nature of parts of the stream-courses traversing the alluvium. This 

 is probably the result of wind-blown dust and sand drifting into 

 such depressions and accumulating during the frequent dust-storms 

 which characterise the hot drv season. 



Petroleum. 

 Natural Indications.— Seepages of tarry oil and bitumen are too 

 numerous on both river banks around and opposite Fathah to be 

 indicated on the map. Bitumen impregnating earth is to be seen 

 at various horizons, and has frequently been forced up vertical 

 fissures. Three separate oil horizons of seeping cellular limestone 

 can be distinctly traced for some distance, passing from one side 

 of the river to the other. Gouls of dark oil are seen conti- 

 nually floating down the river, and have been collected and utilised 

 by the Sappers ; there is a strong odour of hydrogen sulphide on 

 both banks. The water trickling from the small streams into the 

 ^river are milky with suspended sulphur, and specks and patches of 

 this mineral are locally common in the clays and gypsum ; a tarry 



