JABAL HAMRIN AND JABAL MAKHUL. 11 



came from the north-east, being part of that gigantic system of 

 loops which constitute the Himalayan, the Afghan, Baluchistan 

 and Persian mountain systems, we thus remark a tendency for the 

 fold to be pushed over towards the direction of movement. 



The details of the structure are as follows, commencing at the 

 Nukhailah Pass and proceeding north-westwards. The crest of 

 the anticline sinks to a minimum close to and a little east ot this 

 pass, east-south-east of which point it is seen rising gently on a very 

 broad, open, round and regular fold. Across the pass the anticline, 

 omitting slight irregularities on the north-eastern slope is practically 

 symmetrical, while the outcrop of the Fars is reduced to about 

 1£ miles in width. West-north-west of the pass the fold rises very 

 gradually, at first about 2° — 3° but becoming less and less for some 

 2| miles where it reaches a maximum altitude. Beyond, the anti- 

 cline pitches in an equally gradual and gentle fashion for another 

 2 miles, after which it rises again gradually and steadily as far as 

 the word " Jabal " on the \ inch map, where for two or three miles 

 no perceptible pitch is measurable ; at this crest-maximum the Fars 

 outcrop is over 2\ miles in width. It then slowly begins to sink, 

 the pitch gradually increasing to over 5° when a point is reached 

 about a mile from the Tigris where it once more rises very slightly, 

 forming with a short distance of the outcrop on the west bank of 

 the river, a small dome area, which is slightly steeper on its south- 

 western aspect than elsewhere, and whose centre is beautifully 

 shown in the river by concentric ellipses of limestone and gypsum 

 bands, three of the former seeping oil. Up the Jabal Makhul 

 the crest rises, distinctly at first, less and less perceptibly afterwards. 

 Persistent mist prevented my determining the crest-maxima in this 

 range, but there seems to be a long horizontal stretch immediately 

 south of Qalah Jabbar and perhaps another maximum south- 

 south-west of Mushak. Opposite Ain Dibs there is a distinct 

 pitch of 5° to the north-north-west. 



With regard to the flanks of the fold, the dip at Ain Nukhailah rises 

 to 40° on each side. Steeper dips occur locally immediately west-north- 

 west, but where section B-B has been drawn (pis. 1 and 2) tho 

 general maximum dip on the north-east is about 35°, while that on 

 the south-west is between 35° and 40°. On the south-western flank 

 some 5 miles from Fathah a small subsidiary wrinkle makes its 

 appearance and persists for about 3 miles giving vertical an# 

 reversed dips along the Fars boundary ; this is probably a rseult 



B 2 



