56 M1DDLEMISS: GEOLOGY OF HAZARA AND BLACK MOUNTAIN. 



their northern exposures in the Tanawal couptry. The general 

 nature of the melamorphic change in the calcareous members of the 

 series is that what was previously a sub-crystalline or crypto- 

 crystalline rock has now become obviously crystalline to the eye, 

 though except in a few cases the limestone has not become marble. 

 In colours they vary from pale drab to white, veined with grey and 

 enclosing a bright green mineral. Some purple calcareous shales 

 near Kurm have a schistosity developed in them, with slightly curled 

 or wavy surfaces filmed with mica. They correspond faithfully to the 

 similar unmetamorphosed rocks of Sirban hill. The peculiar mode 

 of jointing and weathering of the Infra-Trias limestone, referred to in 

 an earlier chapter, are also characteristic of many of the more northern 

 metamorphosed varieties. 



Of metamorphosed quartzites (or quartz-schists as they had better 

 be called) belonging to this series, there are great thicknesses exposed 

 in Tanawal and the Gundgurh range. Their exact relations to the 

 limestones is not quite clear, but it seems certain that they are not 

 all confined to a position beneath the limestones, and that they 

 therefore represent an arenaceous type of deposit which probably 

 alternated with the calcareous beds along this line of country. It was 

 chiefly owing to the difficulty Wynne found in separating these along 

 their northern boundary from the older schistose representatives of 

 the Slate series that made him hesitate at first to call them and the 

 limestones Infra-Trias, and instead to invent the special name of 

 " Tanols " for them. I have found the difficulty to be equally great, 

 especially for the purposes of close mapping, and so have retained 

 the name "Tanol quartzites " for these somewhat remarkable rocks. 

 I shall have to refer again to this point when the stratigraphical 

 relations of the sections in different zones and areas are described 

 (see Chap. VI, p. 237). For the present I must return to the peno- 

 logical description of them. 



Most of them to the north of Sobruh Gulee in the neighbourhood of 

 Bilihana mountain shew lenticular-tabular foliation to a very advanced 

 degree. Wherever a coarser grain of quartz occurs in the rock it 

 ( 56 ) 



