106 MIDDLEMISS: GEOLOGY OF HAZARA AND BLACK MOUNTAIN. 



hill, both north-east and south-west of it in the neighbouring glens, 

 the position of the Trias against the Infra-Trias is a good example 

 of a sigmaflexure with broken middle limb. In figure 6 I have 

 sketched a view of this, as seen from near the head of the glen 

 running north-west to Sulhud. The middle limb of the inverted 

 fold has given way rather on its northern side, thus leaving much 

 of the trough of the fold in the Trias intact. The sharpness of 

 the inversion may be imagined from the narrow compressed posi- 

 tion of the Spiti shales which occupy the axis of the trough. 

 On the north side of the fault we have a completely normal section 

 down from the felsite through Infra-Trias limestone to the purple sand- 

 stone, which may be seen at one place as indicated in the figure. 

 Looking south-west from the head of this glen under the mass of Sirban 

 the same marked line of break between the Trias and Infra-Trias is 

 visible, the scarped edges of the Trias being very prominent. The line 

 of the fault makes an angle with the vertical somewhat greater than 30 

 and approaching 40 . This causes the Trias to V down into the stream- 

 bed in a very decisive way. In the section, figure 3, page 15 of 

 Waagen and Wynne's memoir the actual line of this junction appears 

 to have been confounded with an ordinary dip plane. Hence the 

 apparent underlie of ordinary Trias limestone beneath the Infra- 

 Trias to the north, and the consequent misunderstanding as to the 

 horizon of the latter. The fault admitted by Waagen and Wynne 

 is placed some way to the south-east along the face of the scarp in 

 the Trias limestone, where the strata are recovering from the dip down 

 against the fault and passing under the peak north-east of Sirban, 

 A comparison of their map with mine will make clear our points 

 of difference. 



The Trias band we are now considering may be very well studied 

 along the spur going north-east from the two-tree hill. The sharp 

 faulted boundary between it and the felsite is clearly seen in plan on 

 the ridge by the way the bare strata of Trias are gradually truncated 

 at a very acute angle by the felsite. This spur is scarped on its 

 south-east side with a well-exposed section of Trias limestone. Near 

 ( 106 ) 



