Kotices of Memoirs — Geological Survey of India. 29 



Himalaya, bordering the Upper Punjab. The geological structure 

 is interesting, as it affords an epitome of much of the geology of the 

 north-west frontier of British India, nearly the whole series known 

 being present; those unrepresented being chiefly the older crystalline 

 and the newer portions of the Tertiary rocks. 



The following is the succession in descending order : — - 



6. — NuMMULiTic. Thick limestones with some shales — fossils in places. 



! Thin-bedded limestones — apparently -without fossils. 

 Impure ferruginous sandy limestone, weathering rusty 

 — fossils. 

 4. — Jurassic. Black Spiti shales. 



Unconformity. 



o rp I Thin-bedded limestones and slaty shales. Dolomite lirae- 



( stone ; fossiliferous [Megaloclon and other) beds. 

 2. — Below the Trias. Haematite, dolomite, quartzite, sandstone, and breccia. 



Unconformity . 

 1. — Semi- Crystalline. Attock (?) slate. 



Two, if not more, unconformities have been observed — 'One between 

 the Jurassic and Triassic series, and the other between the semi- 

 crystalline rocks and the beds above them. 



1. — 'The lowest or Attock slate series are unfossiliferous, but may 

 possibly be of Silurian age. 



2. — The succeeding series is also unfossiliferoiis, and is totally un- 

 conformable to the beds below them. They consist chiefly of red sand- 

 stones, shales, and Quartzitic Dolomites in the lower part; the upper 

 being composed of Dolomites often siliceous, and above which are 

 a third group composed of Hsematitic rocks, sandstones, shales, and 

 breccias. 



3. — 'The Triassic series comprises two divisions, which are either 

 dolomites or limestones ; the lower one containing Megalodon, 

 Dicerocardium, Cliemnitzia, and Gervillia; and the upper one with 

 NerincBa, Neritopsis, Astarte, Opis, Nucula, etc. 



4. The Jurassic beds of Sirban are repi'esented by black shaly 

 clay-beds, well known in Himalayan geology as " Spiti shales." 

 They are not rich in fossils, but fragments of Belemnites, Inoceramus, 

 and Corbida have been fonnd. 



The unconformity of these shales to the underlying Triassic series 

 is marked by the erosion of the limestones, which are also pierced 

 by the crypts of boring Mollusca. 



5. The Jurassic series are overlain, apparently conformably, by 

 hard, rusty, calcareous sandstone, with Cretaceous fossils, chiefly 

 Cephalopods, and a few G-asteropods. The Ammonites belong chiefly 

 to the Gristati and Infiati groups, besides several sjjecies of Ancylo- 

 ceras, Anisoceras, and Bacidites, as well as numerous large Belemnites. 



These fossiliferous beds are considered to be the representatives of 

 the Middle and Upper divisions of the Cretaceous rocks. 



6. Overlying these is a massive grey and blackish Limestone 

 alternating with zones of dark shale, and referred to the Nummu- 

 litic formation. It is of great thickness and much contorted, and 

 its physical features are deeply-excavated gorges and ravines, high 



