Paet :i.] Ball: On the Origin of the Kumaun Lakes. 17!) 
The elevations of the parallel hounding ranges on the north-east and south¬ 
west average upwards of 3,000 feet above the level of the lake, the height of 
■which above the sea has been approximately estimated at 3,400 feet. 
The range on the north is formed chiefly of ■white and purple quartzites, with 
which there are some slates and shales. The dip of these beds is variable, but 
north-west at a low angle seems to be the prevailing direction. Much of the 
higher face of this range is steeply scarped, but landslips abound, and have, to a 
great extent, concealed the character of the lower portions. 
The range on the south consists primarily of an axis of greenstone, which 
stretches continuously hence from the neighbourhood of Bhim Tab Associated 
with this gi’eenstone are quartzites and shales, the beds in immediate contact 
often showing signs of much alteration and induration. Occasionally the effect 
of the former has been such as to cause the affected beds to assimilate to the 
characters of the greenstone, and to be almost inseparable from it, by mere examin¬ 
ation of their out^ward lithological structure. 
What the exact nature of the physical relations of this greenstone may be, 
has not yet been fully ascertained; but that it does not exist merely as a single 
simple dyke is amply testified by the fact that branches from it cross the valley 
at both ends of the lake, and are cut through by the inf ailing and outf ailing 
streams. 
At the head of the lake is a boulder bed through which the river cuts to a 
depth of eight or ten feet. This deposit consists chiefly of subangular fragments 
of trap and quartzite. At first I was inclined to attribute it to the effects of a 
retreating morraine. Temporarily this view was supported by the discovery of 
boulders of granite and gneiss—no hnotun source for which exists within the 
present drainage limits of the Kalsa. It was impossible, however, to overlook 
the fact that there were no signs of polishing on any of the blocks, and that those 
which have come furthest (the granite, &c.) are well rounded and water-worn. 
Taking into consideration the professedly general character of the only existing 
geological map, it would bo clearly unsafe to adopt the view that no source for 
these boulders exists within the -watershed ; and this the more especially as in 
the adjoining basin of the Gola on the north the occurrence of gneiss and granite 
is indicated on the map. 
The importance of determining the source from whence these boulders have 
been derived is sufficiently obvious. If they have not come from within the 
limits of this catchment basin, then indeed it might be necessary to invoke the 
aid of an ice cap to account for their transport; but in the meantime it is 
impossible to assert that this accumulation of boulders at the mouth of the gorge 
is other than a delta of diluvial origin. 
Now as to the character of the lake itself. Its maximum dimensions are, 
length 4,480 feet, width 1,833 feet, and depth 127 feet. Unfortunately, as was 
the case with Bhim Tal, no series of soundings are available, and the form of the 
basin is, therefore, uncertain. The bounding ranges and their slopes, however, 
indicate the V (I’iver) rather than the JJ (glacial) type of valley denudation. 
Looking up the lake towards the course of the stream, the view just beyond 
the gorge is quite shut out by projecting spurs, which a glacier could have scarce¬ 
ly failed to modify, if not remove. 
