part 3 .] Theobald : Ancient. Glaciers of the Kangra District. 
91 
Size of erratics. 
ing from the central peaks of the Dhaoladlulr range, in the form of sinuous streams of 
boulders, rugged, angular, and massive, many of which attain over 50 feet in their greatest 
diameter, they traverse by narrow gorges the range of hills composed of schistose rocks, in¬ 
tervening between the Dhaoladhar range and the plains of the Kdngra district, on reaching 
which they expand, inosculating and coalescing in the open ground to such an extent as to 
cover the greater portion not occupied and defended against invasion by hills. In fact 
Former appearance of Kangra dis- s0 complete was the union of these glaciers that the whole 
trict - of the area shown in the map to have been traversed by 
them must have presented the appearance of one huge ice-field, if we can rely on the 
evidence of the perfect mantle of moraine material which now covers the ground. 
The size of some of the gneiss blocks which have travelled well out into the plains is 
surprising, till the mind fully realises the quasi-omnipotent 
power of the agency involved in their transport. Near 
Busnur south of Rihlu, I measured one block embedded in a field by the roadside, 125 feet 
in girth, and in this and other cases the present dimensions are probably much under the 
original size of the block, from the desquamation of the surface under the action of frost, 
sun, and rain, and in some situations by the friction of stones swept against them by 
streams. Again, between Baglisu and I)arh, four blocks in the immediate neighbourhood 
of the road measured in girth, respectively, 100, 125, 134, and 140 feet. Blocks of this size 
occur, of course, but seldom, but those from 70 to 100 feet somewhat more commonly, whilst 
blocks approaching 50 feet in girth are too numerous to reckon. So great is the abundance 
of the rocky fragments brought down by these glaciers, that the entire country just outside 
the narrow schistose range, which skirts the district to the north, is so covered with them as 
to leave no other rock visible; and hut for the fact that none of these blocks can be seen in 
situ, and for the section occasionally revealed in a deeply cut river bed, the casual traveller 
might very naturally consider the whole area he was traversing to be granite or gneiss. 
The process by which this condition has beon brought about is a very simple one, but at 
Fan-shaped expansion of glaciers tbe same tiim ' beMS P TOof ob the magnitude of 
on quitting the hills. the forces at work, and the duration of the period during 
which they were displayed. On quitting the narrow gorges in the hills wherein they had 
hitherto remained forcibly pent up between rocky walls, the glaciers at once expanded, partly 
through the natural tendency of a piled up mass, possessing the known plastic character ot 
glacier ice, to spread out on a level surface, under the simple operation of gravity, and 
partly to the lateral displacement which later glacial accessions descending such gorges 
would receive from the accumulated moraines of earlier years, heaped up in their direct 
path, either during periodical meltings or during the secular retrocession, probably not u 
continuously uniform process, of the isothermal line of the terminal moraines of the whole 
group of glaciers in question. Exception will doubtless he taken by some to the idea o! 
expansion through plasticity having had any appreciable influence in producing any lateral 
diversion of the moraine when they enter the plains, and I am prepared to admit the. subor¬ 
dinate operation of this cause to the second one I have mentioned, but that it was a vera 
causa to a certaiu extent will, I tbink, be admitted, if due weight is given to the probable 
dimensions vertically of the glaciers in question. If, as has been conclusively established, 
a shallow glacier can quadruple its thickness when compressed between narrow limits, it 
cannot he theoretically denied the power of reassuming a shallower, that is, a more expanded 
form, when, on issuing from the hills, it becomes relieved from all pressure having a ten¬ 
dency to counteract the ordinary effects of gravity on a plastic body, heavily weighted by 
the pressure of the enormous moraines supported by it, which can hardly be so insignificant 
as with time to produce no appreciable result. Thirty or 40 feet is no uncommon thick¬ 
ness for one of these Kangra moraines, and I greatly doubt if in some cases a hundred feet 
