western interior forming an inland lake of any magnitude, even should
there be so anomalous a feature as a depression of the surface in which
it could be collected, especially as our knowledge of its limits indicate
a much drier climate and less favourable conformation of surface than in
the eastern division of the continent. The undulations of the surface of
the country are nearly parallel to the meridian, gradually decreasing in
height from the dividing range between the eastern and western waters
till, instead of the waters of the rivers being confined to valleys, they
occupy plains formed by a slight flattening of the curvature of the
sphere. Thus the sides of the plain through which the river ran before it
turned west to Cooper's Creek were 150 feet below the tangential level of
the centre channels, and even the summit of the sandstone tableland which
rose beyond was below the visible horizon. It is this peculiar
conformation which causes the stream-beds to spread so widely when
following the course of the valleys from north to south, and it is only
where they break through the intervening ridges that the water is
confined sufficiently to form well-defined channels. The existence of
these extensive valleys trending north and south over so large a tract of
country render it by no means unlikely that they continue far beyond the
limits of present explorations, and it is not unreasonable to infer that
the great depression which has been traced nearly five hundred miles
north from Spencer's Gulf through Lake Torrens to the stony desert of
Sturt (or rather the mud plains contiguous to its western limit) may be
continuous for an equal distance beyond to the low land at the head of
the Gulf of Carpentaria; a theory also supported by the fact that the
rivers flowing into the Gulf either come from the east or west,
apparently from higher land in those directions, while there is not a
single watercourse from the south, or any indication of elevated country
in that direction. Captain Wickham having named an important river
discovered by him in H.M.S. Beagle, on the north-west coast, the
Victoria, several years prior to Sir T. Mitchell having attached that
name to the upper portion of Cooper's Creek, which had also been
previously discovered and named by Captain Sturt, I would suggest that
the term River Cooper be adopted for the whole of the main channel from
its sources, discovered by Sir T. Mitchell, to its termination in Lak