8 BENGAL PLANTS. 
eastern half. In the western half the northern portion is occupied 
by the eastern extension of the Upper Gangetic plain, constituting 
to the north of the Ganges the province of Tirhut, to the south of 
aot river we Se of moles Immediately to the south of 
ich forms the north-eastern 
portion of the table- land of Central tndin: south and south-east of 
Chota Nagpur lie the highlands of Orissa and the level country 
between these and the sea. The greater portion of the eastern 
half, from the eighty-seventh to the ninety-second meridian, is 
occupied by Bengal proper and the Sundribuns, or the Lower 
Gangetic Plain and the Gangetic Delta; between the ninety-second 
and ninety-third meridians, to the south of the twenty-sixth parallel 
and east of the Gangetic Delta, lie the hilly tracts of Tippera and 
Chittagong, which, though politically included in our area, belong” 
geographically to Indo-China rather than to India 
The essential features of wei area therefore are siealal of a great 
alluvial plain, with the lower spurs of the Himalayas and a strip 
of submontane forest along its northern border. The longer axis 
of the first or western half of this plain runs, like the river that 
dominates it, from west to east; that of its second or eastern half 
runs at right angles to its fobniee course, from north to south. To — 
the south of its upper or western half, and to the west of its lower _ 
or eastern half, this alluvial plain is again bounded by a fringe of — 
submontane forest, above which rise the escarpments of the plateau 
of Chota Nagpur. The lower or eastern half of this alluvial plain — 
extends towards the north-east into the valleys of the Surma and — 
the Brahmaputra, and is bounded along the south-east border by — 
the submontane forests, and the hilly tracts beyond them, of 4 
Tippera and Chittagong. The submontane forests to the north and 
to the south-west of this plain are characterized by the existence — 
of gregarious tracts of Sal, unknown in the forests to the south- 
east; these latter forests are distinguished by the presence of q 
Gurjan, unknown in the Subhimalayan forests, or in the s 
montane forests of Chota Nagpur. q 
The essential features of the vegetation in the area to the north — 
of the Ganges, from the Gandak on the west to the Brahmaputra ~ 
on the east, as we pass from north to south are as follows. First, — 
a narrow, more or less sloping, gravelly submontane tract along — 
the base of the Himalaya, covered, except along river-beds, with a — 
