102 HAYDEN: GEOLOGY OF TIRAH AND BAZAR VALLEY, 



shales and limestones. Unfortunately circumstances did not allow 

 of my working out these beds in any detail. This would in any case 

 be a matter of considerable time, for although most of the rocks show 

 signs of fossils, chiefly represented by section 

 of bivalve shells, with some gastropods, it was 

 impossible to extract the shells from the hard limestone matrix in 

 which they occur. On the Samara range, the rocks consist of hard 

 grey limestones underlain by sandstones, which in turn are underlain 

 by shaley calcareous beds, the whole series forming an anticlinal, the 

 beds on the south side dipping at high angles, while those on the 

 north have a gentle dip of usually about 20 N. 



The route followed by the troops crossed the Samina range at 



Chagru Kotal. th e> Chagru Kotal, a saddle lying- between 



Gulistan on the east and Dargai 1 on the west. 

 A little to the south of the Kotal are seen the oldest beds exposed 

 in this locality : they consist of reddish sand- 

 stones, with bands of shale and shaley limestone, 

 containing sections of brachiopod shells, and in places remains of 

 ostrea. These beds probably correspond to Mr. Griesbach's horizon 7 

 of (Rec, XXV, p. 81), but owing to the impossibility of recognising 

 any of the fossils, I was compelled to unite the whole series under 

 the term "cretaceous and Jurassic". On crossing the Kotal, the 

 lower beds are overlain by a series of limestones, very hard and 

 containing the remains of many fossils, chiefly gastropoda and lamelli- 

 branchiata. 



About two miles further north, in the Chagru Valley, the lime- 

 stones are succeeded by a bed of hard white 



Chagru Valley. . J 



quartz-sandstone, almost a quartzite, pebbles of 



1 The heights of Dargai— now so famous as the scene of the engagement of Oct. 20th— 

 furnish a good example of the feature so characteristic of all the mountain ranges between 

 Shinawari and the Safed Koh, the beds presenting a steep scarp to the south but to the 

 north falling away in a comparatively gentle slope,-a feature which during the late campaign 

 was of great strategic advantage to the enemy, while equally disadvantageous to the British 

 force attacking the position from the south. 



( 102 ) 



