PART 1.] ^h'3[ahon : Notes of a tour through Ilangrang and Spiti. 
61 
I first met witli gneiss within a few miles of Chango. It showed again 
between the latter place and the Para river, and on the hanks of that stream. 
Dr. Stoliczka identified the gneiss on the loft bank of the Para river as the 
central gneiss (Memoirs, vol. V, p. 16), and though I saw none porphj^ritic in 
structure, I do not doubt the correctness of the identification. That the crys¬ 
talline rocks I have described belong to the central gneiss series may, I think, be 
accepted on the evidence of their crystalline stractui’e, and the j^resenco in them 
of cyanito and inti’usive albite granite, characteristic features of the typical 
Wangtu section. The dip of the crystalline rocks at Leo is west-by-north, but this 
changes gradually to west-south-west, and finally at Chango to south-west. 
About rivo miles south of Chango a I’idgo of limestone rocks, the dip of 
which varies from south-wpst-by-south to south, I’uns up from the Spiti river 
and abuts on the crystalline series just where the road from Leo to Chango 
crosses the ridge. At this point the dip is south-west-by-south. The limestones 
consist of thin-bedded, 2 ^ale blue and cream-colored beds, weathering from a jiale 
pink to a yellow ochre color, intercalated with dark blue calcareous slates. The 
latter effervesced freely wdth acid wherever I tested them, but they break up 
into small thin slices, and look more like slates than limestones. 
In a cliff overhanging the Sj)iti river, I found what appeared to be coralline 
remains in the jpale blue limestone; but they were in bad preservation and have 
not been identified. 
In the bed of a stream to the east of Chango and between the latter village 
and the ridge above described, and also at the village of Chango itself, some hard 
dark slates are exposed. Dr. Stoliczka also mentions (Memoirs, vol. N, p. 19) 
the occuiTence of silurian slates opposite Shalkar. The slates dip under the 
limestones. 
On the north side of Chango the limestones distinctly overlaps up 3 on the 
ciystalline series. To the north-east of the village, where two imgation channels 
“takeoff,” as engineers say, from the stream flow^ing dowm from between the 
Kakthai and Kungi-ang trigonometrical stations to the Sputi river, the crystalline 
series is to be seen in contact with the pink limestones and dai’k calcareous slates. 
Ihe mica schists are riddled with albite giunite veins upj to the point of contact. 
The limestones overlap the schists; and though the pffane of contact dipjs at 
a high angle, the junction of the two series of rocks is evidently not a faulted one, 
for about a mile lower down the stream, the crystalline series again crops up and 
forms a cliff overhanging the river; the identity of these rocks here with those 
higher upt the stream being established by the presence of twm albite granite 
%'eins in the cliff alluded to. Durther evidence of the fact that the limestones 
overlap the crystalline series w'as obtained as I journeyed onwards along the lino 
of strike. 
From Change (elevation 10,15C feet) up to the top of the Chandan Namo 
ghat' (elevation 12,340 feet), the rocks consist of similar linicstonos to those 
' Marked Ga station on tlio map. It is opposite Slialkar, 
