iconic AND KHAETIC. 
loi 
That the upper portion of the limestone mass is of Middle Jurassic 
age, may be inferred from the occurrence of Stephanoceras cf. coronatum 
Brug. in a hmestone band, situated about 370 feet below the base of the 
Spiti shales near Giumal. 
About 1,000 feet below the layer in which Stephanoceras cf. corona- 
tum was found by A. v. Krafft, specimens of Spiriferina cf. obtusa 0pp. 
have been collected between Giumal and Chabrang. This species may 
probably indicate a liassic age for the bed in which it occurs. We may 
therefore assume that approximately 500 feet of the limestone mass 
capped by the Spiti shales belongs to the Jurassic and 800 feet to the 
Triassic system. The middle portion of the limestone series must be of 
liassic age. To define the various horizons accurately within this homo- 
geneous mass, is entirely impossible, owing to the scarcity of determi- 
nable fossils. 
What has been said about the Upper Triassic limestone or Dachstein- 
kalk of Spiti, applies equally to Painkhanda and Johar, the boundary 
between the Triassic and Jurassic systems being not known exactly. 
In the sections examined by Diener' the homogeneous mass of grey 
limestones and dolomites is capped by beds which are certainly 
younger than Triassic. 
Two sections have been described by Diener. One of them, which 
follows the ravine cutting through the rim of the ShalshaJ cliff near 
Shalshal encamping ground, runs as follows : — 
7. Lower Spiti shales, with Belemnites Gerard i 0pp. 
6. Suk'acutus beds, Kelloway : 6 feet. 
5. Yellow-grey, earthy limestones and marls, with Rhijnchonella 
sp. ind.: 4 feet. 
4. Thin-bedded yellow-grey limestones with Belemnites up., 
Ostraea sp., Pecten sp. : 20 feet. 
3. Lithodendron limestone, with crinoid stems : 100 feet. 
2. Thin-bedded limestones, with many bivalves of liassic 
affinities. 
1. Well-bedded limestones, lithologically identical with the 
Upper Triassic Umestones, following above the quartzite 
series. 
1 C. Diener, Ergebnisse, etc., 1. c, pp. 583, 584. 
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