Sec. ii] ALEXANDER'S PASSAGE OF THE HYDASPES 21
view of the river's course right down to Jhelum, and Professor Breloer has justly noted that it was bound to serve as a principal observation post for a
force guarding the left bank. Was it likely that a secret crossing could be safely prepared under its very eyes as it were? In view of this there is no need to stress particularly the fact that even along the somewhat devious route assumed for Alexander's secret march to the proposed crossing place the distance is only a little over 14 miles as against 150 stadia or 17i miles recorded by Arrian.
More important it appears to me to note the total absence in all our accounts of any reference to the very broken character of the ground which stretches
round the position assumed to have been held by Poros in the battle, and which
would have greatly added to its strength. As any detailed survey map shows, torrent beds steeply cut into the clay terrace flank the Naurangabad site both
on the north and south. They would have greatly hampered, if not altogether
precluded, those rapid cavalry movements against the Indian left flank upon which, as Arrian's description clearly shows, Alexander's initial success wholly
depended. To the east where the ground steadily rises towards the Pabbi range,
the flat ground rapidly narrows. Within a mile or so beyond the assumed defensive horseshoe formation of Poros it becomes so furrowed by small ravines
that the great turning movement assigned to Koinos's horse against the enemy's right could not have been executed in time to aid the main attack. It would seem strange if such important features of the ground, greatly favouring the defence, had been left wholly unnoticed in the Greek accounts of the hard contested victory if it really had been gained here.
But the attention just drawn to the actual features of the supposed battle-field opposite Jhelum may claim more than a negative value. If the consideration due
to them be extended to the whole terrain flanking what may briefly be described
as the eastern bridge-head of the Jhelum passage, it must become clear how difficult it would be for an invader from the north-west to force this passage if held
in strength on the left bank. We have seen already that the great torrent beds to the north, boggy even in the `cold weather' season, together with the furrowed hills drained by them, make approach to this bridge-head from higher up the river very difficult.
A look at any large-scale survey map will show that Nature has made the approach to it equally difficult along the river below. There the steep Pabbi
range drawing nearer sends down to the left bank a continuous succession of ravines, large and small. They intersect the narrow strip between the river and the foot of the hills to such an extent as to render rapid movement or deployment very difficult for any large body intended to attack that bridge-head from the south. If we add to this the facilities for defence which the Pabbi range