DESCRIPTIVE. 



71 



The Upper Helmand and Kabul Valleys. 



Reference has already been made to the rocks seen in the mountains 



between Bamian and the Helmand [supra, pp. 

 Paimurl and Kalu. ^ n n _ k ' . . . , 



23, 25, 54). The Kalu river, rising behind the 



village of the same name, in the snow-capped granite peaks of the 



Koh-i-Baba, cuts its way across almost the whole width of the range, 



and issuing through a gorge second in grandeur only to Tangi 



Gharu, joins the Bamian river at Kala-i-Zohak. For the last two miles 



of its course it runs through the conglomerates and sandstones of the 



Bed Grit series. "Where it issues from the gorge at Paimuri, it passes 



under two natural bridges of travertine deposited from the saline 



springs which rise along the Koh-i-Baba fault [supra, p. 51; see also 



20, 531). The gorge itself is carved through the Kalu series of 



gneiss, quartzite and slate ; it is about a mile and a half in length, and 



at the upper end was formerly blocked by a landslip, which has resulted 



in the checking of the current above and the consequent formation of a 



wide valley of erosion the bottom of which is filled with river deposits, 



through which the river meanders. Above this ' chaman ' and at 



about two miles below Kalu, the conglomerates already mentioned 



[supra, p. 23) are seen along the road and are between 200 and 



300 feet thick. The graphitic schists are seen in the hills on the right 



side of the river, opposite Kalu caravansarai. The valley here is strewn 



with blocks of hematite of all sizes, which have been derived partly from 



the high ridge to the north-east, and partly from small ridges and 



outcrops a few hundred yards away to the south-east and south. On 



the way up to the Kotal-i-Hajigak, the fossiliferous limestone crops out 



at the foot of the pass on the left side of the road, 



where the latter meets a stream flowing down from 



the north. It appears to be overlain by the Helmand series of slate and 



quartzite. All the beds dip more or less steadily to the south, but the 



structure is complicated by numerous subsidiary folds. Limestone crops 



out again on the north side of the pass near the top and appears to dip 



to the north but lower down on the west side the southerly dip is quite 



clear. 



