158 
THE VEGETTATION OF THE ZEMU 
and natural features were quite different from anything we had 
met with so far. 
We spent the following two days exploring the flats and screes 
near the junction of the two streams, the liungma Chu and tlie 
Nahu Chu, whose union gives the Llonakh. Both streams are 
turbulent and icy cold but as they have not the violent downhill 
rush of the Llonakh they can be forded at several places in their 
course. Caution is necessary as at this time of the year the volume 
is considerable. . 
These flats form a wonderful expanse of gently undulating 
ground in the midst of the highest peaks in the Himalayas. They 
extend up both the affluents of the Llonakh, but those along the 
Lungma Chu are more extensive than those up the Naku Chu and 
vary in breadth from one to three miles. They are the level floor 
^formed by the aition of some huge glacier or rather set of con- 
verging glaciers that have long ago disappeared or are now repre- 
sented by comparatively small glaciers at the heads of all the 
valleys. There is no area in Sikkim wliich is quite the parallel of 
the Llonakh area. Sliould climatic conditions ever permit of the 
disappearance of the huge Zemu glacier, a similar basin would no 
doubt be found to lead up to the base of Kangchenjunga. 
Here and there on the flanks are huge moraines, — accumulations 
of mighty boulders, — with a very limited flora sheltering in the 
crevices. These moraines begin at 14,500 feet and extend up to 
the existing glaciers. Once inside the Llonakh area the traveller 
finds his road easy as there is only the fording of the icy streams to 
hinder his march. The lower hills skirting the flats are rounded 
and smoothed as by a plane ; covered with snow for nearly nine 
months of the year and with a short dry summer they have not 
lost the outlines given, them by the action of the ice-field of previous 
ages. Above these hills the higher peaks have the craggy out- 
lines and jagged rocks of the ty]ucal East Himalaya. The flats 
themselves are not continuous. Here and there the valleys con- 
tract to defiles and these lead to other flats at higher levels. At 
some intermediate epoch these flats were glacial lakes and in places 
the depth of alluvium is considerable. The streams of to-day are 
scoring deep channels in this alluvium. This is specially noticeable 
at the junction of the two streams where the river lies quite twenty 
feet, below the level of the surrounding plain. High up in the side 
valleys the same formation is being worked out on a much reduce<l 
scale. Small lakes in shallow basins are found regularly a short 
way below the foot of each glacier. 
