1854.] Notes on tlw Geology of the Punjab Salt Range. 675 



developed, and the original planes of stratification with deep ripple 

 markings in places well preserved. The prevailing colour of the 

 slate is gray, stained red and yellowish, and weathering to a dark 

 burnished brown, in which state it presents an intensely ferruginous 

 and burnt aspect, relieved by occasional veins of pure white quartz. 

 These veins occur with no regularity and are rarely of any thickness. 

 Much peroxide of iron is associated with these rocks, and a curious 

 carbonate of lime and iron (vide Mr. Piddington's examination of 

 the ore, J. A. S. Vol. XXII. p. 208), resembling a rich carbonate of 

 iron, but, in reality, rather a carbonate of lime, occurs associated with 

 the quartz veins. One of the largest veins observed was about one foot 

 in thickness, half consisting of pure white quartz, the rest of the 

 curious carbonate of lime and iron examined by Mr. Piddington. 



I now come to the consideration of rocks of an igneous character, 

 which, it has been asserted, occur nowhere throughout the Salt Range. 

 Trap however undoubtedly occurs at some few places towards the 

 east end of the range, and in other places signs of a metamorphic 

 action having been exerted on the rocks are pretty plain. On the 

 southern descent of Mt. Tilla, the upper strata are seen much 

 shattered and re-cemented by stalactitic infiltrations, and many beds 

 of shale appear greatly altered and strongly impregnated with iron. 

 This very circumstance may be perhaps rather the cause than the 

 effect, for I need only quote " laterite" as an instance of what sin- 

 gularly deceptive and protean aspects, a rock containing much iron is 

 capable of putting on. The Karana rocks also afford striking 

 instances of that pseudo-slaggy appearance that some ferruginous 

 rocks exhibit, so that perhaps these appearances on Mt. Tilla can- 

 not safely be referred to metamorphic action properly so called. 

 An instance again occurs in the JNTilawan ravine below JNurpur, where 

 two beds of sandstone are seen much altered and thrown up at 20° 

 BT. N. W., crossing the gorge something in the manner of a low 

 wall. Between them a ferruginous trap rock occurs, which alters 

 and hardens the adjoining rocks to a depth of eighteen inches, and is 

 thus the cause of their standing up like a blackened wall from among 

 the soft unaltered strata. Near Mari also many beds of sandstone 

 appear altered by hot vapours traversing the planes of stratification 

 though to no great extent, the action scarcely affecting more than 



