THE KIRKUK ANTICLINE. 4j 



tightness of the folding coincides with a closer proximity to the 

 origin of the folding movement, which proceeded from the north-east. 



Rocks. 



Fars series. — The Fars consists of the usual sequence of gypsum, 

 limestone and clays. Amongst the limestones is the noticeable 

 pelecypod bed, an old shell-bank crowded with small pelecypods. 

 and having a superficial resemblance to a nummulitic limestone. 

 Bright red clays are especially prominent in the neighbourhood of 

 Ivirkuk. The uppermost bed is sometimes a gypsum band, 

 sometimes a fossiliferous limestone ; a little below is a thin layer of 

 reddish sandstone similar to that of the succeeding series. 



Kurd series.- — The Lower stage of the Kurd series consists of the 

 usual red clays and current-bedded sandstones, the former pre- 

 dominating near the base and producing natter and more rounded 

 topography, the latter increasing upwards and producing the series 

 of characteristic ridges indicated on the map. Thick beds of light 

 reddish clay again appear in this stage, however, as it passes up into 

 the Upper or Conglomerate stage. In the latter pinkish or yellowish 

 red clays are prominent, the colour being less intense than that 

 of the earlier argillaceous deposits. The boundary line between 

 the two stages was taken as the base of the first thick conglo- 

 merate, which produces outstanding physical features in the form of 

 a line of loftier round-topped ridges. It is an artificial boundary 

 since thin inconstant conglomerates occur below it, but it has been 

 selected as being easy to identify and map. Deposition has been 

 uninterrupted from the Lower to the Upper stage. The most pro- 

 minent conglomerate forms a curiously regular even range, extend- 

 ing with scarcely a break for a great many miles, and providing 

 many streams of excellent water on both sides, at any rate during the 

 winter months. As the map shows, the Lesser Zab and the Qarah 

 Chai are the only two streams which pierce the part of this range 

 under description, which is known variously as the Shamasin Dagh, 

 the Baba Gurgur, and the Jabal Buar. Its sky-line is a monotonous, 

 almost unbroken, slightly denticulate line, and its dip-slope presents 

 such a characteristic appearance of intricate dissection combined 

 with rounded outlines — due to the easy disintegration of the con- 

 glomerates and the soft, interbedded clay bands — as to be recogniz- 

 able many miles distant. North-eastwards it is covered by high- 

 lying Alluvium. 



D 



