Val. IV, No..9.] The Kosi River. 471 
[N.S.] 
intense than such earthquakes as that of 1897 ; the effects of that 
Shock are not properly known; certain areas in the plains were 
certainly depressed, but how far these depeeimiens were only due 
to local conditions of sub-soil, etc., we have no knowledge. 
: was noticed after the earthquake of 1897, by several old 
and experienced Indigo Planters in North Bihar, that” many minor 
streams, in and near the Siwaliks, changed their courses consider- 
ably ; it is well known that in oe a minor changes are 
not of infrequent occurrence, and that nature has not yet ‘assigned 
anything like permanent levels to ee Siwalik regions ; at the sa 
time she seems to be on the balancing point between secure ied 
insecure levels. After the ear thquake, the Nepal Darbar caused an 
ir i into the changes in stream beds to be made, but 
heavy silt-carrying capacity, and consequently severe rock-abraising 
power, might yield information that at one time a river had passed 
over what is now a dipin the Siwalik ranges. Surveyors, too, 
could throw light on the situation by measuring the heights of 
' existing depressions in the Siwaliks above the pr esent course of the 
western arm of the Kosi within the hills. 
The past, present, and future history of that portion of the 
river lying within the hills has now been dealt with ; its case is 
very different from that of the portion occupying the plains; in the 
hills the function of the river is to carry away, as fast as possible, 
all débris and matter it can pick up, carry, and pus ng, and also 
such material as itis able to transport in solution ; the river is 
with matter to be transported in a number of ways, the details of 
which need not be entered into here ; the chemical and mechanical 
denudation of the hills are the feeding agents, and a pants of 
these two agents is outside the scope of this note. On re g 
t 
constructive in its action; the plains themselves are formed almost 
entirely by sys river from ‘deposits placed layer upon es deposits 
carried from t} s dur 
e hills and built up by slow processe ing many 
ore of pedi The plains section of the river is at the present 
mom in construction work; at some future time, as 
will cor seen later, its final life-object will be completed by the 
assumption of destructive action, during which stage, having first 
levelled its catchment area to the level of its plain area, it wi ‘ill, by 
slow degrees, reduce both to the level of the sea; until then the 
cure with which nature originally created the river cannot be 
nally fulfilled; every river, except the mountain torrent which 
renee itself directly into the sea, into a large lake or another 
stream close to the hills, must pass through three stages of existence, 
