1842.] of the Himmalay a Mountains. xcix 



220. It was observed, that sometimes the change from the green 

 schist to the quartz rock was sudden; sometimes a real transition is 

 seen. In general, the schist has a stronger resemblance to the chloritic 

 types, though it is also found a perfect hornblende schist. The dip and 

 inclination of the strata present great local irregularities, the former 

 being sometimes reversed within a few hundred yards, and the latter 

 not unfrequently 90°. The direction appears to follow a curved line, 

 being in the first instance observed as conformable, i. e. N. W. It 

 is then seen to run N., from which point it gradually changes to N. 

 35° E. In the first case the dip was as usual N. E. ; as the direction 

 changes, the strata become wedge-shaped, and assume a vertical position, 

 till at length it is found that the dip is reversed, being finally S. E. 



221. From the bed of the Nullah, the route ascends to Dhunpore, 

 where are worked the most valuable and productive copper mines in 

 the mountains. The rocks which are found in the ascent to the 

 Koangola Pass and descent thence are various in character, and a more 

 enlarged examination of this neighbourhood is required to determine 

 their true relations to each other. In the ascent to Dhunpore, quartz 

 rock is the prevailing substance, which passes on the summit of 

 the ridge into a very thin slaty rock of a yellowish colour, exceed- 

 ingly hard, and composed apparently of quartz with some talc. The 

 laminae of this are not above a tenth of an inch in thickness. They 

 separate with greatest clearness, are often bent or curved, are rather 

 brittle, and consequently not obtainable of any size. This type might 

 be called slaty quartz rock, in contra- distinction to schistose quartz rock. 

 It passes into the pure amorphous type; argillaceous schist, then 

 succeeds, variously intermixed with limestone more or less pure. 

 The former occurs here of an intense black colour, similar to that of 

 basanite. It has a schistose structure, but never separates into thin 

 slates, the attempt to obtain such generally producing a conchoidal 

 surface, or at least one more or less uneven. It is moderately hard, 

 of a fine grain, receives a good polish, would form a most superior descrip- 

 tion of writing slate, and is not even inapplicable to the purposes 

 to which basanite is applied. It has a cleavage, or set of natural 

 joints, the surfaces of which present the appearance of a slight iri- 

 descence, or pavonine tarnish. This cleavage is most commonly, 

 or at least very often, transverse to the direction of the schistose 



