SAIGHAN. 



6] 



In Ao dara the Doab series consists of volcanic ash, breccia and 

 beds of trap. It is overlain to the north by the Upper Cretaceous 

 limestone, and to the south is replaced by the grey saccharoid limestone, 

 which is locally seamed with black basaltic dykes. 



Turning now to lower Saighan, the rocks in the valley below 

 Saraiak are greatly disturbed. On the left side 

 of the valley at Delchi, the plant-bearing series is 

 very conspicuous (Plate 11). It consists of dark shales with many 

 well preserved fossil plants and some insignificant coal-seams. The 

 lowest bed seen here is Cretaceous limestone dipping under the Saighan 

 series along the overthrust already referred to {supra, p. 58). At a 

 short distance below Delchi a bed of conglomerate belonging to the 

 Doab series occupies the centre of the valley and, being harder than the 

 neighbouring rocks, has retarded the erosive action of the river ; the 

 result has been the formation of a narrow gorge with precipitous sides. 

 On the right side of this gorge, the old slate and schist series is over- 

 lain unconformably by the Doab conglomerate and this again on both 

 sides of the gorge is capped, also unconformably, by the Upper Creta- 

 ceous limestone (see Plate 14). On the hills on the right side of the 

 valley, the Cretaceous limestone is covered by horizontal beds of con- 

 glomerate, presumably of Upper Tertiary age. 



Below the Delchi gorge, the valley rapidly widens again. It has 

 been eroded out of the soft shales of the plant-bearing series which is 

 very conspicuous below Khwajaganj, on the slopes below the Kotal-i- 

 nalifarsh. Here the river takes a sudden turn to the right and again 

 cuts its way through the conglomerate and shale of the Doab series, 

 which is replaced, below Baiani, by schist and gneiss, presumably the 

 easterly extension of the graphitic series of Saraiak. At Bagh-i-Haibak 

 there is an extensive development of the volcanic beds of the Doab 

 series which is probably continuous along the gorge of the river down 

 to Doab-i-Mekhzarin. 



The valley of the Surkhab below Doab is clearly the structural 

 continuation of lower Saighan, and the same rock-series continue 



