24 MIDDLEMISS: GEOLOGY OF HAZARA AND BLACK MOUNTAIN. 



hand-specimens the rock is very characteristic, so characteristic that it 



would be almost impossible to mistake it for anything else when once 



the peculiarities have been mastered. These peculiarities consist 



chiefly in a fine cross-jointing which has been eaten into deeply by 



weathering, so that the blocks of the rock scattered about present an 



appearance very like that of a butcher's chopping-board which has 



become scored across and across in all directions by the knife. I do 



not remember to have seen elsewhere any surface weathering at all 



resembling this, which is so persistent as to at once arrest the eye. 



In the upper beds of the limestone there is a tendency to a 



vesicular structure on a small scale, the vesicles, which are about the 



size of pea, being filled with calcite. 



In the uppermost layers of the limestone there are many bands of 



chert lying parallel to the bedding. These 

 Chert bands. , 



bands appear to owe their presence chiefly to the 



metamorphic effects of the volcanic series which come next at the 



base of the Trias. 



Many of these limestones were called dolomites by Wynne and 



Waagen. A rough analysis of three samples. 



Composition. ° ° J r > 



one from Shakur Bandee, a pink variety, 

 (Registered No. - E ^) i one from Bandah Naiyan, and one from ridge 

 north of Tanakki, vesicular variety (Reg. No. ¥ |^), shows them to 

 contain a small amount of magnesia, but not sufficient to make 

 the rock a typical dolomite. The examinations were made by 

 Mr. Blyth in the Geol. Survey Laboratory. 



Among the upper limestones there are here and there associated 

 Beds of white a few beds of white felspathic grit of no parti- 



felspathicgrit. cular importance. 



Much of the Infra-Trias limestone of the north face of Sirban 

 hill was confused with the Trias by Waagen and 



Partly confused with 



Trias by Waagen and Wynne, in their memoir and map. In the de- 

 ynr scriptive part of this paper (see p. \Qi t et seq.) I 



have endeavoured to trace the origin of this mistake. 

 ( 24 ) 



