iAIGHAN. 



57 



Saighan and Kahmard. 



Tlic cap of Cretaceous limestone which apparently covers Koh-i- 

 Ghandak does not extend as far westwards as the Kotal-i-Katar 

 sum. Intrusive igneous rocks are plentiful and may belong- to the 

 group so largely developed in the valley below the village of Ak 

 Robat. To the north of the pass the rocks are quartzite, slate, phyllite 

 and graphitic slate and schist which I refer to the Helmand series. 

 At a few miles below the pass a belt of granite interrupts the sedi- 

 mentary sequence and extends to below Sokhta Chinar. Beyond this 

 and not far from Saraiak, the sedimentary rocks re-appear and consist 

 of quartzite and slate ; they are followed by gneiss and serpentine, the 

 former being perhaps a product of the metamorphism of the arena- 

 ceous members of the Helmand series by the basic intrusions. Con- 

 spicuous masses of crystalline limestone can be seen high up on the hills 

 to the west of Sokhta Chinar ; they include many varieties, some 

 white and coarsely crystalline, others fine-grained saccharoid marble, 

 either white or dark grey. I believe these to be the representatives of 

 the Fusulina limestone series of Ak Robat, the advanced stage of 

 alteration being due to the intrusive granite. 



Below Sokhta Chinar the hills on the right side of the valley are 

 capped by Cretaceous limestone and Tertiary conglomerate, lying in 

 almost horizontal beds and with striking unconformity on the old 

 slates (Plate 7). The slate series is presumably that termed by 

 Mr. Griesbach the '* anthracite group " of Saighan and regarded by 

 him as Permo-Triassic. I have referred it to the Helmand series which 

 I class tentatively as Carboniferous. Mr. Griesbach regarded it as 

 younger than the massive limestone of the gorge below Ak Robat, and 

 consequently referred it to the Permian and Lower Trias. His inter- 

 pretation of the section between Bamian and Saighan is in fact exactly 

 the reverse of mine. His observations were made under very trying 

 circumstances (see footnote to page 53) to which must be attributed his 

 impression that the beds on the south of the Ak Robat Kotal were 

 dipping steadily to the north-west. If such were the dip, the relative 



