HAYDEN : GEOLOGY OF NORTHERN AFGHANISTAN. 



of the Kalu and Helmand series — with a certain amount of granite, 

 which, however, is chiefly confined to the higher peaks. Between this 

 backbone of old rocks and the Tertiary deposits on the flanks of the 

 range, there is a strip of Mesozoic beds, consisting chiefly of Cretaceous 

 limestone with here and there a patch of the lied Grit series cropping out 

 from below. These are separated from the slates and quartzites by a fault 

 which appears to run all along the northern side of the Koh-i-Baba in 

 Bamian. It has been met with behind Koh-girdak (6 miles S. S. W. of 

 Taibnt), again in the upper reaches of the Chapdara a little further to 

 the east, and also on the northern side of the belt of gneiss at the mouth 

 of the Paimuri gorge. It probably continues eastward to Irak and 

 possibly across the Shibar pass into Ghorband. This, however, is onlv a 

 suggestion, as we know nothing of the higher hills between Paimuri and 

 Shumbal. 



On the left side of the Bamian valley, the Tertiary beds cover the 

 Khwajagar and greater part of the southern flanks of the Koh- 



Koh-i-Qhandak. {.Qhandak on the north of Taibut. They are 



never very thick, probably not more than a few hundred feet, as the 

 underlying rocks, on all of which they lie unconformably, frequently 

 crop out more or less unexpectedly. A few miles above Taibut, the 

 Cretaceous limestone appears to spread over the flanks of the hills 

 all along the left side of the valley, and never to be very far below 

 the surface. At about two miles to the north-east of Taibut, in the 

 Khwajagar ravine, erosion has laid bare the underlying rocks which are 

 chiefly hard dark limestone with a little slate. The limestone is like 

 that in the gorge above Ziarat Chashma Shafan, between Bamian and 

 Ak Robat, and is overlain by Fusulina limestone similar to that of the 

 Shumbal-Balula section. The latter rock is well seen at about 4 miles 

 above the mouth of the valley. Fmulina are very plentiful, and 

 almost every boulder or pebble lying in the valley-bottom is full of 

 them. A very conspicuous and common species is F. elongata Shumard, 

 which is found at the point marked 1 on Plate 8, fig. 2. Above this 

 is the brachiopod horizon (supra, p. 27) and some distance above 



