4_) PASCOE: GEOLOGICAL NOTES ON" MESOPOTAMIA. 



The thickness of the Lower stage opposite Panj Ali, works out 

 at over 7.000 feet. The thickness of the whole series must be over 

 32.000 feet, a river deposit rivalling in size as it resembles in charac- 

 ter and age, the great Siwalik deposit of India. 



Mesopotamia.)} Alluvium. — As in former maps the boundary of 

 the Alluvium indicated is merely the approximate limit of Tertiary 

 exposures, and has no tectonic significance. 



Structure. 



It will be advisable to consider first the Panj Ali area in the 

 extreme south, where the structure is clearer, and proceed thence 

 north-westwards, examining these more obscure portions in the light 

 of the more complete succession in the south-east [see map, pi. 5). 



In the Panj Ali area, reviewing the section from north-east to 

 south-west, the Conglomeratic stage on the north-eastern flank of 

 the anticline passes down into the Lower stage of the Kurd series 

 dipping at angles varying between 40° and 50° ; approaching the 

 Fars, however, the dip diminishes gradually to 35° and 30°, and 

 then rapidly steepens to 50° and 60°. The dip along the north- 

 eastern fringe of the Fars outcrop is here about 00° ; this is followed 

 by minor puckering and contortion, but a distinct arch of rather 

 more importance than those of the puckers can be made out along 

 the centre of the outcrop, and, from all appearances, may be accepted 

 as the crest of the main anticline. Further to the south-west 

 vertical dips and further contortion follow, until the boundary 

 between the Fars and the Kurd series is reached. Here the dip in 

 both is 25° in an E.N.E. direction, showing considerable reversal ; 

 the junction appears normal, the beds of the newer series consisting 

 of the red clays characteristic of the lowest horizons. We have 

 here, therefore, a tight, compressed, overfolded, contorted isocline, 

 the overfolding being in the direction of the folding movement, 

 i.e., to the south-west. Small slips and faults are seen in the south- 

 western limb where small minor wrinkles have given way under the 

 compressional strain. I have tried to illustrate in a somewhat 

 diagrammatic way the type of fold in sketch-section B-B (pi. 5). 



Proceeding north-westwards from the Panj Ali area, we find 

 the arch of the crest disappears, and judging from the narrowing 

 outcrop and sinking topography, the fold pitches. Two miles 

 south-east of Kirkuk it commences to rise again, but the dips are 

 all north-easterly and the Fars outcrop is invaded by the Alluvium. 



