Such tides as set towards the Himalaya broke against their farther buttresses, leaving an interesting ethnographical flotsam in the northern valleys; but they never overflowed the Himalayan barrier.
The hade of the fault is constantly inwards, towards the centre of the chain, and the older rocks which form the Himalaya proper, have been pushed forward over the later beds of the sub-Himalaya.
The genera common to the Himalaya and Europe are much more abundant, and extend throughout the chain, and to all elevations.
The general conformation of the Hindu Kush system south of the Khawak, no less than such fragmentary evidence of its rock composition as at present exists to the north, points to l its construction under the same conditions of upheaval and subsequent denudation as are common to the western o Himalaya and the whole of the trans-Indus borderland.
The Indo-Gangetic depression was formed by the weight of the over-riding mass bending down the edge over which it rode, or else it is the lower limb of the S-shaped fold which would necessarily result if there were no fracture - the Himalaya representing the upper limb of the S.
From such causes the physical conditions of a large part of Asia, and the history of its population, have been very greatly influenced by the occurrence of the mass of mountain above de Iiima- scribed, which includes the Himalaya and the whole tayan elevated area having true physical connexion with that boundary.
Of these the only genus that is not found on the Himalaya is Fagus.
Its upheaval above the great sea which submerged all the north-west of the Indian peninsula long after the Himalaya had massed itself as a formidable mountain chain, belongs to a comparatively recent geologic period, and the same thrust upwards of vast masses of cretaceous limestone has disturbed the overlying recent beds of shale and clays with very similar results to those which have left so marked an impress on the Baluch frontier.
In India it extends from the Punjab to the northwestern frontier, ascending in the Punjab Himalaya to a height of 650o feet, and is found both in the wild and cultivated state.
On the outer ranges of the Himalaya the yearly fall amounts to about 200 in.