Himalayan Journals, vol 2 - J. D. Hooker (bill gates best books txt) 📗

countless streams from its perpetual snows, glaciers, and small lakes: its north drainage is to the Cholamoo

lakes in Tibet; in which is the source of the Lachen, which flows

round the north base of Kinchinjhow to Kongra Lama.

The bottom of the Lachoong valley at Momay is broad, tolerably level, grassy, and covered with isolated mounds and ridges that point down the valley, and are the remains of glacial deposits. It dips suddenly below this, and some gneiss rocks that rise in its centre are

remarkably moutonneed or rounded, and have boulders perched on

their summits. Though manifestly rounded and grooved by ancient

glaciers, I failed to find scratches on these weather-worn rocks.* [I have repeatedly, and equally in vain, sought for scratchings on many of the most conspicuously moutonneed gneiss rocks of Switzerland.

The retention of such markings depends on other circumstances than

the mere hardness of the rock, or amount of aqueous action. What can be more astonishing than to see these most delicate scratches

retained in all their sharpness on rocks clothed with seaweed and

shells, and exposed at every tide, in the bays of western Scotland!]

The Lachoong is here twelve or fifteen yards wide, and runs over a

pebbly bed, cutting a shallow channel through the deposits, down to the subjacent rock, which is in some cases scooped out six or eight feet deep by its waters. I do not doubt that the flatness of the

floor of the Momay valley is caused by the combined action of the

streams that drained the three glaciers which met here; for the

tendency of retiring glaciers is to level the floors of valleys, by giving an ever-shifting direction to the rivers which drain them, and which spread detritus in their course. Supposing these glaciers to

have had no terminal moraines, they might still have forced immense beds of gravel into positions that would dam up lakes between the ice and the flanks of the valleys, and thus produce much terracing on the latter.* [We are still very ignorant of many details of ice action, and especially of the origin of many enormous deposits which are not true moraines. These, so conspicuous in the lofty Himalayan valleys, are not less so in those of the Swiss Alps: witness that broad valley in which Grindelwald village is situated, and which is covered to an immense depth with angular detritus, moulded into hills and valleys; also the whole broad open Upper Rhone valley, above the village of

Munster, and below that of Obergestelen. The action of broad glaciers on gentle slopes is to raise their own beds by the accumulation of

gravel which their lower surface carries and pushes forward. I have seen small glaciers thus raised 300 feet; leaving little doubt in my mind that the upper Himalayan valleys were thus choked with deposit 1000 feet thick, of which indeed the proofs remain along the flanks of the Yangma valley. The denuding and accumulating effects of ice

thus give a contour to mountain valleys, and sculpture their flanks and floors far more rapidly than sea action, or the elements. After a very extensive experience of ice in the Antarctic ocean, and in

mountainous countries, I cannot but conclude that very few of our

geologists appreciate the power of ice as a mechanical agent, which can hardly be over-estimated, whether as glacier, iceberg, or pack

ice, heaping shingle along coasts.We are still very ignorant of many details of ice action, and especially of the origin of many enormous deposits which are not true moraines. These, so conspicuous in the

lofty Himalayan valleys, are not less so in those of the Swiss Alps: witness that broad valley in which Grindelwald village is situated, and which is covered to an immense depth with angular detritus,

moulded into hills and valleys; also the whole broad open Upper Rhone valley, above the village of Munster, and below that of Obergestelen.

The action of broad glaciers on gentle slopes is to raise their own beds by the accumulation of gravel which their lower surface carries and pushes forward. I have seen small glaciers thus raised 300 feet; leaving little doubt in my mind that the upper Himalayan valleys were thus choked with deposit 1000 feet thick, of which indeed the proofs remain along the flanks of the Yangma valley. The denuding and

accumulating effects of ice thus give a contour to mountain valleys, and sculpture their flanks and floors far more rapidly than sea

action, or the elements. After a very extensive experience of ice in the Antarctic ocean, and in mountainous countries, I cannot but

conclude that very few of our geologists appreciate the power of ice as a mechanical agent, which can hardly be over-estimated, whether as glacier, iceberg, or pack ice, heaping shingle along coasts.]

On our arrival, we found that a party of buxom, good-natured looking girls who were tending yaks, were occupying the hut, which, however, they cheerfully gave up to my people, spreading a black tent close by for themselves; and next morning they set off with all their effects packed upon the yaks. The ground was marshy, and covered with

cowslips, Ranunculus, grasses and sedges, Cyananthus, blue

asters, gentians, etc. The spot appearing highly favourable for

observations, I determined to remain here during the equinoctial

month, and put my people on "two-thirds allowance," i.e., four

pounds of rice daily for three men, allowing them to send down the

valley to cater for what more they could get. The Singtam Soubah was intensely disgusted with my determination: he accompanied me next day to the pass, and having exhausted his persuasions, threats, and

warnings about snow, wind, robbers, starvation, and Cheen sepoys,

departed on the 12th for Yeumtong, leaving me truly happy for the

first time since quitting Dorjiling. I had now a prospect of

uninterruptedly following up my pursuits at an elevation little below that of the summit of Mont Blanc, surrounded by the loftiest

mountains, and perhaps the vastest glaciers on the globe; my

instruments were in perfect order, and I saw around me a curious and varied flora.

The morning of the 9th of September promised fair, though billowy

clouds were rapidly ascending the valley. To the eastward my

attention was directed to a double rainbow; the upper was an arch of the usual form, and the lower was the curved illuminated edge of a

bank of cumulus, with the orange hues below. We took the path to the Donkia pass, fording the river, and ascending in a north-east

direction, along the foot of stony hills that rise at a gradual slope of 12 degrees to broad unsnowed ridges, 18,000 to 19,000 feet high.

Shallow valleys, glacier-bound at their upper extremities, descend

from the still loftier rearward mountains; and in these occur lakes.

About five miles up, a broad opening on the west leads to Tomo Chamo, as the eastern summit of Kinchinjhow is called.* [On one occasion I ascended this valley, which is very broad, flat, and full of lakes at different elevations; one, at about 17,000 feet elevation is

three-quarters of a mile long, but not deep: no water-plants grew in it, but there were plenty of others round its margin. I collected, in the dry bed of a stream near it, a curious white substance like thick felt, formed of felspathic silt (no doubt the product of glacial

streams) and the siliceous cells of infusoriae. It much resembles the fossil or meteoric paper of Germany, which is also formed of the

lowest tribes of fresh-water plants, though considered by Ehrenberg as of animal origin. A vein of granite in the bottom of the valley

had completely altered the character of the gneiss, which contained veins of jasper and masses of amorphous garnet. Much olivine is found in the fissures of the gneiss: this feral is very rare in Sikkim, but I have also seen it in the fissures of the White gneissy granite of the surrounding heights.] Above this the valley expands very much,

and is stony and desert: stupendous mountains, upwards of 21,000 feet high, rear themselves on all sides, and the desolation and grandeur of the scene are unequalled in my experience. The path again crosses the river (which is split into many channels), and proceeds

northwards, over gravelly terraces and rocks with patches of Scotch alpine grasses (Festuca ovina and Poa laxa), sedges, Stipa,

dandelion, Allardia, gentians, Saussurea, and Astraga1us,

varied with hard hemispherical mounds of the alsineous plant

mentioned at chapter xxi.

I passed several shallow lakes at 17,500 feet; their banks were green and marshy, and supported thirty or forty kinds of plants. At the

head of the valley a steep rocky crest, 500 feet high, 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 by barometer, and 17,866 by boiling-point.

The view on this occasion was obscured by clouds and fogs, except

towards Tibet, in which direction it was magnificent; but 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 1500 feet below me, at the

bottom of a rapid and rocky 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 one side, and from

Donkia on the other: the Lachen flowed from its northern extremity, and turning westward, 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, from north to

north-west, 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 (20,000 feet) the vast snowy mountains that rose beyond it were, I was assured, beyond the Yaru, in the salt lake country.* [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 soda, "Pleu" of the Tibetans.] A spur from Chomiomo cut off the view to the southward of north-west, and one from Donkia concealed all to the east of north.

Illustration--TIBET AND CHOLAMOO LAKE FROM THE SUMMIT OF THE DONKIA PASS, LOOKING NORTH-WEST.

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 comparatively gently sloped, and of a yellow red

colour, rising and falling in long undulations like dunes, 2000 to

3000 feet above the mean level of the Arun valley, 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 that immense area was very open and undulating, like the great ranges of Central Asia, described by MM. Huc