52 HAYDEN : GEOLOGY OF SPITI. 
resembling a slate with embedded boulders of all sizes, ranging up to 
nearly a foot in diameter. This character is particularly noticeable 
along the path between Pomarang and M&ni on the right side of the 
river, and also between Po and Dankhar, on the left bank, at a short 
distance below the point at which the path first begins to ascend on 
to the mesozoic beds; this locality is mentioned by General McMahon, 
who correlated the conglomerate with the Blaini boulder-slate of 
Simla.^ The same rock crops out again at the junction of the Lingti 
andSpiti rivers,^ where it was subsequently examined by Mr. Oldham,* 
who also adopted General McMahon's correlation with the Blaini rock.* 
It has already been stated that the uppermost beds of the palaeozoic 
group consist of a bed of calcareous sandstone 
Calcareous san sto overlain by black shales, and that the two beds 
are seen in all sections, resting at times on the lower silurian quart- 
zite or the upper silurian limestone, as in the Thanam valley ; at 
times on the carboniferous limestone, as in the Pin valley ; or underlain, 
as in lower and upper Spiti and Kanaur, by the conglomerates just 
describ^-d (see PI. HI, fig- 3)- The lower part of the calcareous sand- 
stv>re is coarse and conglomeratic, but the thickness of the conglo- 
merate is often only a few feet. The sandstone is ever > wh re tos- 
siliferous, but the fossils are usually badly preserved. The collections 
made from this bed were also sent to Dr. Diener, who has kindly fur- 
nished the author with the following list of brachiopods found among 
them : — 
Spirifer fasciger, KeyserWng { = Sp. musakheylensis, Dav.). 
„ nittensis, Diener. 
J, marcout, Waagen. 
„ distefanii, Geinmellaro. 
Spifigera gerordi, Diener. 
Dielasma la Touchei, Diener (n. sp.). 
Streptorhynchus cf. pectiniformis, Dav. 
Aulosteges cf. gigas, Netsch. 
1 Records, G. S. I., vol. XII, p. 63. 
' Ibid., p. 64. 
' Records, G. S. I., vol. XXI, p. 151. 
* See below, chapter VIU. 
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