THE INDIAN PENINSULA I51

(which in prehistoric days was probably a tributary of
the Indus) is an important factor in the agricultural development
 of India, and sustains an immense irrigation
system ; but neither the Jumna nor any other river of
India approaches the Ganges in general works of benefcence.
 For not only does the Ganges exercise a great
function as land maker and fertilising agent, but she has
ever served as the great national highway of India from
the Bay of Bengal to the north-west.
Between Agra and Allahabad many a large tributary
joins the Jumna from the native states of Central India
which occupy the long northern slopes of the central
plateau; and one important river, the Son, unites with
the Ganges near Patna after draining the north-western
hills of the Chota Nagpur division of the Bengal province.
The Central India tributaries all take their rise from the
crest of the Vindhya hills overlooking the deep valley of
the Narbada. The Son rises in the historic mountains of
Amarkantak, from whence also the Narbada takes its rise
and flows westward ; thus these two rivers together form
a transverse system right across India from Patna to
Broach, which has practically no northern basin or
i catchment area” at all. On the southern slopes of the
mass of elevated tableland which culminates at Amarkantak
 commence also the headwaters of some tributaries
of these great rivers, which find their exit in the Bay of
Bengal, i.e. of the Mahanadi and the Godavari.
Central India and that part of the Bengal province
which is included in Chota (or Chutia) Nagpur is infinitely
varied in its general appearance and character. Here commences
 the forest country, which with occasional modificasions
 covers the whole of the eastern highlands of India.
In Central India the hills are broken and separated
into groups and clusters, rising some hundreds of feet
(seldom more than 1oco) above the general level of the
tableland, which is itself from 1500 to 2000 above sealevel.
 Often these hills are marked by precipitous cliffs
surrounding their summits, and rendering all efforts to
approach them difficult and dangerous. Hundreds of