by climbing some thirty feet from the ground, a night's repose,
or at least a night undisturbed by their attacks might be obtained.

Hastening back to the boats, we pushed on, but were some time getting to
the end of the reach, the shallowness of the water rendering our advance
difficult and tedious; entering at length the next, which trended
South-West for about half a mile, the river gradually widened out until
it attained a breadth of about half that space. An extensive flat of sand
fronted the eastern bank, which was very low, and though now dry, bore
undoubted marks of being not unfrequently visited by floods. The western
bank of the next reach was low and broken, evidently forming a group of
low grassy islands when the river is in a higher state.

Some yellow sandstone cliffs, from ten to sixteen feet in height, formed
the opposite bank of this reach, which extended barely a quarter of a
mile, in from a South by East to a South by West direction; and varied in
width from one to two hundred yards. We now entered a lake-like reach of
the river, trending south for a mile and a quarter, having a breadth of
about a hundred yards, and a depth in many places of twelve feet; being
twice that which we had usually found in any of the lower reaches, with
scarcely any stream. Soon after entering this remarkable sheet of water,
we noticed a rock formation in its western banks; this we found to be a
coarse-grained red sandstone, with fragments of quartz, and extended for
nearly a quarter of a mile along the edge of the water. Over many parts
of it was a coating of a dark and metallic appearance, about three inches
thick; and the surface in places presented a glazed or smelted
appearance. Mr. Darwin, in his work upon volcanic islands, page 143,
alludes to this formation, under the head of "Superficial ferruginous
beds," and thus concludes his observations: "The origin of these
superficial beds, though sufficiently obscure, seems to be due to
alluvial action on detritus abounding with iron."

As we proceeded along this canal, for such was the appearance of the
reach we were now ascending, we surprised a small party of natives. They
were at the water's edge, beneath a high mound of loose white sand, over
which the children were some time in making their escape, struggling and
screaming with anxiety and fear, as they half buried themselves beneath
its treacherous surface; and sometimes, after almost gaining the summit,
sliding bac