280 
Eeconlx of the Geological Survey of India. 
[voL. xin. 
precise ratio of such fluidity least capable of # # bearing upon their 
surface craggy masses of rock, such as I should term erratics” (supra, p. 165). 
The examination of the landslip under comsideration disposes of this objection; 
for though most certainly such ‘ craggy masses of rock ’ were not born on the 
surface of the semi-liquid mass, yet there were numbers such floated in its sub- 
stauce, many of which now show at the surface, several being 9 or 10 feet in length 
exposed ; and I have no hesitation in saying that were this landslip on a larger 
scale—for it must not be forgotten that compared with several others in the 
lulls around it is insignificant in size—and left untouched by the hand of man, it 
would, when cut into by rain and streams, show many if not all those features 
which are sujjposed to be especially characteristic of a moraine. 
As to the question whether the barrier of the Naini Tal basin is a landslip 
or a moraine, I shall not here enter into its discussion ; this, however, I must say, 
that the profile of the slope to the east of the outlet bears every appearance 
indicative of a large landslip having fallen there. On the hill side there is no 
bulging, but a straight sweep down to a comparatively level terrace, through 
whicli the stream forming the outlet of the lake has cut down for some distance. 
Whether the lake was formed by the landslip, or whether this was subsequent to 
the formation of the lake, I am not prepared to assert dogmatically ; but this 
I believe, that in past times thei'e has been a great landslip from the slopes of the 
Kalikhan, and that on this old slip are placed the hospital and convalescent depot. 
The recent slip shows cleaidy that a large landslip can extend across and fill 
up a valley, and at the same time may show that mixture of rocks of all sizes 
which forms one of the chief features of a moraine; and it is not improbable 
that, under favourable circumstances, it might resist the wash of a stream over 
it and so form a permanent lake. In the case of Mulwa Tal, one would certainly 
su^jpose from the look of the ground that if its existence is not due to a landslip, 
yet the level of the water must at one time have been raised some twenty or thirty 
feet higher than it now stands, by a great landslip which has undoubtedly fallen 
from the hills to the ea.st of the outlet in times which may not date further back 
than one or two hundred years, and are certainly later than much that geologists 
woidd speak of a.s recent. 
But if a lake is to be formed by a landslip, it must not merely be one of 
those which are cverywhei'o to be seen, caxised by the cuttings of a stream into 
the base of the slope, hut lather one of those which take many years and even 
centuries preparing, as has been the case with this small one at Naini Tal, and 
which when they fall do not come down in a stream of fragments, but with one 
great rush, which would carry them right across the valley and raise the surface 
to such a height that, by the time the dammed-up water reached high enough to 
overflow, the debris would have had time for the water mixed with it to drain off 
somewhat, and would hav^e settled down sufficiently to withstand the wash of the 
stream running over it. Such ca.ses have been known, but the dam has always 
given way; yet it is not inconceivable that in some cases which have happened 
in fhat remote pa.st, of which we have no knowledge but what is written in the 
rocks, some few baiTiers so made were able to stand and form what are now 
kuuwn as the Kumaun lakes. 
