GEOLOGY. 
5 
fined. This area has somewhat the form of an oblong, with the longer axis north-west and 
south-east. Its north-eastern boundary is formed by the Indus, whilst the south-western bound¬ 
ary is far less regular, and, bulging out near the southern corner, includes a considerable tract 
of country about Spiti, Kulu, and Lahaul. The south-eastern limit of the area examined is 
formed by a line drawn north-north-east from Simla to the Indus, the north-western extrem¬ 
ity being near Kargil and Eras. The south-western boundary is formed first by the range 
which separates the Kashmir valley from that of the Indus, and the continuation of the same 
in the Zaskar range as far as the Baralatse or Baralacha pass, whence the boundary turns 
southward and embraces the country between the Baralatse range and the snowy ridges north 
of the Sutlej valley, near Simla. 1 
The general formation of the mountains near Simla is too irregular for any definite range 
of great length to he distinguished. The ridges throughout the North-Western Himalayas 
and Western Tibet have a general north-west and south-east direction, shown by the main 
course of both the mountains and river valleys; and this direction is, of course, due in a great 
measure to the strike of the various rocks, and the outcrop of softer or harder strata. Com¬ 
mencing at the south, 2 the range north of the Sutlej, opposite Simla, usually considered the true 
Himalaya, and well known to all visitors to Simla as the snowy range, is chiefly composed of the 
rock called by Hr. Stoliczka “ central gneiss.” 3 The mineralogical character by which this rock is 
distinguished is the presence of albite in large quantities, with quartz, orthoclase, and biotite, 
and a still more marked peculiarity in the constant occurrence of veins of albite granite, 
which traverse the mass in every direction. 
To the south of the central gneiss various metamorphie rocks are found: to the north or 
north-east of it commences the sedimentary area of Tibet. It is palpable that this central 
gneiss is not only pre-silurian in age, but that it must, in all probability, have been metamor¬ 
phosed before the deposition of the silurian strata. Hence its importance: for whilst other 
metamorphie formations of the Himalayas and Tibet are, probably, represented by fossiliferous 
sedimentary deposits in other parts of the range, the central gneiss appears to belong to an 
older period altogether. 
To the north-west this gneissic formation extends but a short distance. The natural 
continuation of the range formed by it would be the Pir Panjal, south-west of Kashmir; but 
this consists of newer formations. Hr. Stoliczka was inclined to consider the Zaskar ridge as 
the probable continuation of the central axis, as he considered it, and to look upon the gneiss 
of which that range consists as the representative of the central gneiss. It, however, wants 
the albite granite. 
The highest peaks of the snowy Himalayan range consist of silurian rocks dipping 
northward, and followed in ascending order by carboniferous, triassic, and jurassic strata. 
1 For convenience sake, it maybe as well to point out that tlie principal ranges of tbe North-Western Himalaya and Western Tibet, 
all running nearly north-west and south-east, are, commencing on the north, the Kuenluen range on the edge of the Yarkand plain; 
the Mastagh range traversed by the Karakoram pass, and forming the main ridge, separating the Indus watershed from that of the 
Yarkand plain; the Ladak range running along the northern (or north-eastern) hank of the Indus, and separating its valley from 
that of the Shayok; the Zaskar range, which forms the south-western limit of the Indus drainage, extending along the north-eastern 
boundary of Kashmir, and the continuation of which to the south-west is sometimes known as the Baralatse range, and the Hima¬ 
laya proper, the north-western continuation of which is the Pir Panjal. 
3 The account which follows is derived in great part from Mr. H. B. Medlicott’s sketch of the Geology of the Panjab and its 
dependencies in the Pan jab Gazetteer. 
3 Some important additional information concerning this rock has recently been furnished by Colonel C. A. McMahon, who has 
determined by microscopical examination that this gneiss possesses the characters of an igneous rock, in parts at all events, and that 
it must probably have been in a more or less plastic or fluid state.—Records, Geol, Surv. Ind., X, p. 222. 
b 
