64 



ITAYDEX : GEOLOGY OF NORTITERX APGHAKISTAN. 



beds of the Saighan series which have been locally altered to slate and 

 limestone, thus proving that volcanic activity persisted into the Jurassic 

 period. 



The Saighan series passes up through conglomerate into the Red 



Grit series. At the gorge at the head of the 

 Isbpushta. . . 



lshpushta valley the following section is found 



(in descending order) : — 



7. Upper Cretaceous limestone. 



6. Sandstone with beds of gypsum. 



5. Conglomerate. 



4. Bed pisolitic bed, like laterite. 



3. Hard red limestone with Rudistse. 



2. Red sandstone. 



1. Red conglomerate. 



The lowest of these beds is the typical conglomerate, of which the 



greater part of the Red Grit series is composed ; beds 2 to 4 are the 



upper part of the same series and indicate merely slight modification in 



the conditions of deposition. Bed 5, however, inaugurates a complete 



change ; the remarkable red colour disappears and the conglomerate and 



overlying sandstone and gypsum belong to the Upper Cretaceous 



limestone (7) rather than to the underlying red beds. There appears 



to be a slight hut distinct unconformity at the base of the conglomerate 



(5). At the same time the presence of Rudista confirms the views 



already expressed, as to the Cretaceous age of the Red Grit series. 



To the east of lshpushta, the Saighan series continues over the 



Kotal-i-Khaki towards Barfak, eventuallv dis- 

 Barfak and Tala. . 



appearing under the recent talus tans winch cover 



the valley -bottom (Plates 15 and 16) . The lower beds have been altered 

 by dykes from the underlying volcanic series. Below Barfak on the 

 way to Tala the same conditions have been noticed among the small 

 hills through which the road passes. Tala was the easterly limit of my 



