DARJEELING TO TONGLO. 57 
the intense winter's cold and nocturnal radiation under a clear sky, are 
equally fatal to the rich, succulent, herbaceous, and arboreous native vege- 
tation of the Cis-Himalayan mountains, as the extraordinary uniformity 
with respect to solstitial temperature and humidity in the latter region 
are to a perennial exuberance of vegetable life, and to the ascent of 
tropical plants to elevations far above those heights which we should 
consider their superior limit, did we argue from the influence of mean 
temperature alone. 
On ascending Tonglo, we left cultivation and groves of poor Peach- 
trees on its flanks at Simonbong, altitude about 4,000 feet, the average 
level to which agriculture reaches in a great part of Sikkim. This is 
a remarkable contrast to either the north-western Himalaya, or to 
Bhootan, in both of which countries crops are raised abundantly at 
6,000 to 8,000, and even to 10,000 feet and upwards ; and it is owing 
to many local causes ; some of which, as that the Lepchas prefer dwelling 
at about that elevation, and the restless life they lead, are obvious ; while 
others, drawn from natural peculiarities, are of extreme complexity. 
Sikkim I have always held to be a peculiar nook of the Himalaya, 
differing much in some of its features from either Nepal in the 
west or Bhootan in the east; and I am hardly adequately prepared 
to point out all the prominent features. 1. As a segment of the 
Himalaya, it is narrower than the average; the snowy mountains of 
its northern boundary are nearer the plains of India than those of 
Bhootan and Nepal are, although their peaks attain a higher ele- 
vation than any known Asiatic or other mountains in the world. 
2. It is cut off from Bhootan by a long meridional snowy ridge with 
peaks 17,000 feet, running thirty miles south from the main range, a 
very rare if not unique phenomenon in the. Himalaya. 3. Transverse 
ranges also divide it from Nepal, striking north from Tonglo to the 
snow, and averaging 12,000 feet in height. 4. A longitudinal ridge 
(Sinchul mountain, on a northern spur of which Darjeeling stands) 
separates it from the plains of India. 5. Innumerable ridges, without 
any arrangement, all reaching 7 to 12,000 feet, are enclosed within 
these four walls; themselves are intersected by profound ravines, and 
forest-clad up to and over their summits. 6. What we know of the 
geology of the country is, that it is remarkably uniform, of crumbling - 
gneiss and mica-schist hills, much more continuously wooded than those : 
of Bhootan, where dry and barren hills of mountain Limestone occur, - 
and where are also broad valleys, equally unknown in Sikkim. 7. Bya — 
VOL. II. I 
