frontier town.

From a ruined Roman fort which crowns a low hill at the south end of
the town we have our first view of the cataract, and the sudden change
in the character of the scenery is remarkable.

In place of the broad fields and mountains to which we have been
accustomed, the river here flows in a basin formed by low, precipitous
hills, and is broken by innumerable rocky islets on different levels,
which form the series of rapids and little cascades which give the
cataract its name. These little islets are formed by a collection of
boulders of red granite filled in with silt, and have a very strange
effect, for the boulders are rounded by the action of the water,
which, combined with the effect of the hot sun, has caused the red
stone to become coated with a hard skin, black and smooth to touch,
just as though they had been blackleaded.

Many of the islets are simply rocks of curious shapes which jut out of
the water; others are large enough to be partially cultivated, and
their little patches of green are peculiarly vivid in contrast with
the rock and sand which form their setting.

The scenery is wildly fantastic, for while the rocks which form the
western bank are almost entirely covered by the golden sand-drifts
which pour over them, smooth as satin, to the water's edge, those on
the east are sun-baked and forbidding, a huge agglomeration of
boulders piled one upon the other and partially covered by shingle,
which crackle under foot like clinkers; between are the islands, many
crowned by a hut or pigeon-cote, and with their greenery often
perfectly reflected in the rapidly flowing water.