he lake, threw themselves down and took many
swallows before discovering their mistake; but the effect was not
injurious except that it increased their thirst. A few mezquite trees
and a chenopodiaceous shrub bordered the lake, and on these our mules
munched till they had sufficiently refreshed themselves, when the call
to saddle was sounded, and we groped silently our way in the dark. The
stoutest animals now began to stagger, and when day dawned scarcely a
man was seen mounted.

"With the sun rose a heavy fog from the south-west, no doubt from the
gulf, and, sweeping towards us, enveloped us for two or three hours,
wetting our blankets and giving relief to the animals. Before it had
disappeared we came to a patch of sun-burned grass. When the fog had
entirely dispersed we found ourselves entering a gap in the mountains,
which had been before us for four days. The plain was crossed, but we
had not yet found water. The first valley we reached was dry, and it
was not till 12 o'clock, M., that we struck the Cariso (cane) creek,
within half a mile of one of its sources, and although so close to the
source, the sands had already absorbed much of its water, and left but
little running. A mile or two below, the creek entirely disappears. We
halted, having made fifty-four miles in the two days, at the source, a
magnificent spring, twenty or thirty feet in diameter, highly
impregnated with sulphur, and medicinal in its properties.

"The desert over which we had passed, ninety miles from water to water,
is an immense triangular plain, bounded on one side by the Colorado, on
the west by the Cordilleras of California, the coast chain of mountains
which now encircles us, extending from the Sacramento river to the
southern extremity of Lower California, and on the north-east by a
chain of mountains, running southeast and northwest. It is chiefly
covered with floating sand, the surface of which in various places is
white, with diminutive spinelas, and everywhere over the whole surface
is found the large and soft muscle shell. I have noted the only two
patches of grass found during the 'jornada.' There were scattered, at
wide intervals, the Palafoxia linearis, Atriplex, Encelia farinosa,
Daleas, Euphorbias, and a Simsia, described by Dr. Torrey as a new
species.

"The southern termination of this desert is bounded by the Tecate chain
of mountains and the Colorado; but its northern and eastern boundaries
are undefined, and I should