IIAYDEN : GEOLOGY OF NORTHERN AFGHANISTAN. 



Hindu Kush is a single range, the " Northern Hindu Kush " just men- 

 tioned, while the Koh-i-Baba and other ranges to the south of the Ghor- 

 band and Panjshir valleys are the continuation of the Kailas range. It 

 is doubtful if either of these alternatives will entirely meet the case. 



Plate 1 is the result of an attempt to determine the chief orographic 

 trend-lines of the Afghan water-parting and neighbouring areas; it has 

 been derived from the North-West Transfrontier sheets (1 inch = 4 miles) 

 of the Survey of India, by reduction by pantograph. It must be 

 remembered that the geology of by far the greater part of this area is 

 unknown and it is impossible to say therefore how far the apparent 

 trend-lines can be regarded as truly orogenic. Where, however, we 

 have geological information, as in the extreme west and again over 

 much of the eastern part of the country, we find that the main 

 topographic features conform with considerable accuracy to the tectonic 

 conditions and it is fair to assume that similar relations prevail in the 

 intervening areas. Working on this assumption we see that between 

 Tirich Mir and Persia the trend-lines follow a curve which is convex 

 towards the south ; beginning with a N.E. - S.W. direction they 

 gradually bend through E.-W. to S.E. - N.W., which latter trend 

 would carry them on through the mountains of Persia to meet the 

 system of the Caucasus. 



The most striking feature in this diagram is the great trough 

 which extends almost continuously from the Kotal-i-Anjuman at the 

 head of the Panjshir valley, through Ghorband, Bamian and the Hari 

 Rud to Herat. In the eastern valleys its direction is strictly that of 

 the axes of the neighbouring folds ; similar conditions appear to prevail 

 also to the east of Herat, but what happens in the interval of some 

 250 miles we do not know. To the west of Herat the Hari Rud 

 soon bends away to the north and presumably loses its parallelism to 

 the tectonic trend-lines. From Mr. Griesbach's description of the 

 country to the west and north-west of Herat it would appear that a 

 continuous belt of Upper Palaeozoic rocks extends from Khorasan south- 

 eastwards to the Doshakk mountains and thence eastwards to the 

 Davendar range ; it is therefore cut through by the Hari Rud to the 



