(Diatomacese). I t much resembles the fossil or meteoric
paper of Germany, which is also formed of the lowest
tribes of fresh-water plants, though considered by
Ehrenherg as of animal origin. At the head of the
valley a steep crest rises between two precipitous
snowy peaks, and a very fatiguing ascent (at this
elevation) leads to the sharp rocky summit of the
Donkia pass, 18,466 feet above the sea. The view on
this occasion was obscured by clouds and fogs, except
towards Tibet, in which direction it was magnificent;
hut as I afterwards twice ascended this pass* and also
crossed it, I shall here bring together all the particulars
I noted.
The Tibetan view, from its novelty, extent, and
singularity, demands the first notice : the Cholamoo
lake lay 1,500 feet below me, at the bottom of a rapid,
descent; it was a blue sheet of water, three or four
miles from north to south, and one and a half broad,
hemmed in by rounded spurs from Kinchinjhow on the
one side, and from Donkia on the other: the Lachen
flowed from its northern extremity, and turning west-*
ward, entered a broad barren valley, bounded on the
north by red stony mountains, called Bhomtso, which
I saw from Kongra Lama, and ascended with Dr,
Campbell in the October following; though 18,000 to
19,000 feet high, these mountains were wholly unsnowed.
Beyond this range lay the broad valley of
the Arun, and in the extreme north-west distance, to
the north of Nepal, were some immense snowy mountains,
reduced to mere specks on the horizon. The
valley of the Arun was bounded on the north by very
precipitous black rocky mountains, sprinkled with
snow; beyond these again, snow-topped range rose
over range in the clear purple distance. The nearer
of these was the Kiang-lah, which forms the axis or
water-shed of this meridian; its south drainage being
to the Arun river, and its north to the Yaru-tsampu:
it appeared forty to fifty miles off, and of great mean
elevation: >lne vast snowy mountains that rose beyond
it were,/I was assured, beyond the Yaru, in the salt-
lake -country.* A spur from Chomiomo cut off the
vbsw to the southward of north-west, and one from
/ Donkia concealed all to the east of north.
The most remarkable features of this landscape were
its enormous elevation, and its colours and contrast to
the black, rugged, and snowy Himalaya of Sikkim.
All the mountains between Donkia pass and the Arun
were of a yellowish red colour, rising and falling in long
undulations like dunes, and perfectly bare of perpetual
snow or glaciers. Rocks everywhere broke out on
.their flanks, and often along their tops, but the general
contour of the whole immense area was very open
and undulating, like the great ranges of central Asia
described by MM. Hue and Gabet. Still further, the
mountains were rugged, often rising into peaks, which
from the angles I took here, and subsequently at
Bhomtso, cannot be below 24,000 feet, and are probably
higher. The most lofty mountains were on the range
* This salt country was described to me as enormously lofty, perfectly
sterile, and fourteen days’ march for loaded men and sheep from Jigatzi :
there is no pasture for yaks, whose feet are cut by the rocks. The salt is
dug (so they express it) from the margin of lakes ; as is the carbonate of