SIAH KOS. 



1,1 



this area the rocks consist of slate, limestone and calc-sehist, evidently 

 the products of metamorphism of a sedimentary series. No fossils have 

 been found in them and they may be of almost any age. 



Limestone continues practically all the way from Ali Masjid to 

 Landi Kotal, where it is succeeded by a thick series of slates. At 

 about 8 miles from Landi Kotal on the road to Dakka the slate series 

 is interrupted by a fault which brings in some thick-bedded limestone ; 

 this, however, soon gives place again to slate which is apparently 

 the prevailing rock in the hills all round Dakka. 



From Dakka onwards the road runs first through slate, then on to 

 alluvium interrupted here and there by older rocks. Beyond Basawal 

 it passes through a low hill-range of slate, calc-schist and limestone, 

 all greatly crushed, contorted and metamorphosed. Thence a broad 

 alluvial plain stretches up to and beyond the village of Chahardeh 

 (Chardih), to the east of which a low ridge of limestone runs towards 

 the river to join the Koh-i-Bedaulat. 



From Chahardeh the Jalalabad road continues in a north-westerly 

 direction through the plain for several miles, but, just beyond Lachi- 

 pura, runs on to the right bank of the Kabul river and skirts cliffs of 

 quartz-schist and sericite schist, the latter with well-marked slaty 

 cleavage. Similar rocks continue as far as Giridi Kach, where they 

 give place to serpentine, with dolerite and a small amount of phyllite. 

 These form the northern end of a group of hills composed chiefly of 

 basic igneous rocks. Thence an open plain, interrupted only by some 

 small granite hillocks at Jalalabad, extends to the foot of the Siah-Koh. 



The Siah Koh and neighbouring valleys. 



The main road from Jalalabad to Kabul runs via Gandamak to 

 Jagdallak. On the right is the Siah Koh with 



BelWe Gan J dI a n lak ad its schists and limestones, and far away on the 



left the forest-clad slopes of the Safed Koh. The 

 intervening depression is filled chiefly with "pepper-and-salt" sand- 

 stone and conglomerates, with occasional shaly bands, all presumably of 



