THE MAKE OF THE DESERT
[Sidenote: Sea of sand.]
The first going-down into the desert is always something of a surprise.
The fancy has pictured one thing; the reality shows quite another
thing. Where and how did we gain the idea that the desert was merely
a sea of sand? Did it come from that geography of our youth with the
illustration of the sand-storm, the flying camel, and the over-excited
Bedouin? Or have we been reading strange tales told by travellers of
perfervid imagination--the Marco Polos of to-day? There is, to be sure,
some modicum of truth even in the statement that misleads. There are
“seas” or lakes or ponds of sand on every desert; but they are not so
vast, not so oceanic, that you ever lose sight of the land.
[Sidenote: Mountain ranges on the desert.]
[Sidenote: Plains, valleys, and mesas.]
What land? Why, the mountains. The desert is traversed by many mountain
ranges, some of them long, some short, some low, and some rising upward
ten thousand feet. They are always circling you with a ragged horizon,
dark-hued, bare-faced, barren--just as truly desert as the sands which
were washed down from them. Between the ranges there are wide-expanding
plains or valleys. The most arid portions of the desert lie in the
basins of these great valleys--flat spaces that were once the beds
of lakes, but are now dried out and left perhaps with an alkaline
deposit that prevents vegetation. Through these valleys run arroyos or
dry stream-beds--shallow channels where gravel and rocks are rolled
during cloud-bursts and where sands drift with every wind. At times the
valleys are more diversified, that is, broken by benches of land called
mesas, dotted with small groups of hills called lomas, crossed by long
stratified faces of rock called escarpments.
[Sidenote: Effect of drought.]
With these large features of landscape common to all countries, how
does the desert differ from any other land? Only in the matter of
water--the lack of it. If Southern France should receive no more than
two inches of rain a year for twenty years it would, at the end of that
time, look very like the Sahara, and the flashing Rhone would resemble
the sluggish yellow Nile. If the Adirondack region in New York were
comparatively rainless for the same length of time we should have
something like the Mojave Desert, with the Hudson changed into the red
Colorado. The conformations of the lands are not widely different, but
their surface appearances are as unlike as it is possible to imagine.
[Sidenote: The effect of rains.]
For the whole face of a land is changed by the rains. With them come
meadow-grasses and flowers, hillside vines and bushes, fields of yellow
grain, orchards of pink-white blossoms. Along the mountain sides they
grow the forests of blue-green pine, on the peaks they put white caps
of snow; and in the valleys they gather their waste waters into shining
rivers and flashing lakes. This is the very sheen and sparkle--the
witchery--of landscape which lend allurement to such countries as New
England, France, or Austria, and make them livable and lovable lands.
[Sidenote: Harshness of the desert.]
[Sidenote: A gaunt land.]
But the desert has none of these charms. Nor is it a livable place.
There is not a thing about it that is “pretty,” and not a spot upon it
that is “picturesque” in any Berkshire-Valley sense. The shadows of
foliage, the drift of clouds, the fall of rain upon leaves, the sound
of running waters--all the gentler qualities of nature that minor
poets love to juggle with--are missing on the desert. It is stern,
harsh, and at first repellent. But what tongue shall tell the majesty
of it, the eternal strength of it, the poetry of its wide-spread
chaos, the sublimity of its lonely desolation! And who shall paint the
splendor of its light; and from the rising up of the sun to the going
down of the moon over the iron mountains, the glory of its wondrous
coloring! It is a gaunt land of splintered peaks, torn valleys, and hot
skies. And at every step there is the suggestion of the fierce, the
defiant, the defensive. Everything within its borders seems fighting to
maintain itself against destroying forces. There is a war of elements
and a struggle for existence going on here that for ferocity is
unparalleled elsewhere in nature.
[Sidenote: Conditions of life.]
[Sidenote: The incessant struggle.]
The feeling of fierceness grows upon you as you come to know the desert
better. The sun-shafts are falling in a burning shower upon rock and
dune, the winds blowing with the breath of far-off fires are withering
the bushes and the grasses, the sands drifting higher and higher are
burying the trees and reaching up as though they would overwhelm the
mountains, the cloud-bursts are rushing down the mountain’s side and
through the torn arroyos as though they would wash the earth into the
sea. The life, too, on the desert is peculiarly savage. It is a show
of teeth in bush and beast and reptile. At every turn one feels the
presence of the barb and thorn, the jaw and paw, the beak and talon,
the sting and the poison thereof. Even the harmless Gila monster
flattens his body on a rock and hisses a “Don’t step on me.” There is
no living in concord or brotherhood here. Everything is at war with its
neighbor, and the conflict is unceasing.
[Sidenote: Elemental warfare.]
Yet this conflict is not so obvious on the face of things. You hear no
clash or crash or snarl. The desert is overwhelmingly silent. There is
not a sound to be heard; and not a thing moves save the wind and the
sands. But you look up at the worn peaks and the jagged barrancas, you
look down at the wash-outs and piled bowlders, you look about at the
wind-tossed, half-starved bushes; and, for all the silence, you know
that there is a struggle for life, a war for place, going on day by day.
[Sidenote: Desert vegetation.]
[Sidenote: Protruding edges.]
How is it possible under such conditions for much vegetation to
flourish? The grasses are scanty, the grease wood and cactus grow in
patches, the mesquite crops out only along the dry river-beds. All
told there is hardly enough covering to hide the anatomy of the earth.
And the winds are always blowing it aside. You have noticed how bare
and bony the hills of New England are in winter when the trees are
leafless and the grasses are dead? You have seen the rocks loom up
harsh and sharp, the ledges assume angles, and the backbone and ribs
of the open field crop out of the soil? The desert is not unlike that
all the year round. To be sure there are snow-like driftings of sand
that muffle certain edges. Valleys, hills, and even mountains are
turned into rounded lines by it at times. But the drift rolled high
in one place was cut out from some other place; and always there are
_vertebræ_ showing--elbows and shoulders protruding through the yellow
byssus of sand.
[Sidenote: Shifting sands.]
The shifting sands! Slowly they move, wave upon wave, drift upon drift;
but by day and by night they gather, gather, gather. They overwhelm,
they bury, they destroy, and then a spirit of restlessness seizes them
and they move off elsewhere, swirl upon swirl, line upon line, in
serpentine windings that enfold some new growth or fill in some new
valley in the waste. So it happens that the surface of the desert is
far from being a permanent affair. There is hardly enough vegetation to
hold the sands in place. With little or no restraint upon them they are
transported hither and yon at the mercy of the winds.
[Sidenote: Desert winds.]
[Sidenote: Radiation of heat.]
Yet the desert winds hardly blow where they list. They follow certain
channels or “draws” through the mountain ranges; and the reason for
their doing so is plain enough. During the day the intense heat of
the desert, meeting with only a thin dry air above it, rises rapidly
skyward leaving a vast vacuum below that must be filled with a colder
air from without. This colder air on the southern portion of the
Colorado Desert comes in from the Gulf region. One can feel it in
the passes of the mountains about Baboquivari, rushing up toward the
heated portions of Arizona around Tucson. And the hotter the day the
stronger the inward rush of the wind. Some days it will blow at the
rate of fifty miles an hour until sunset, and then with a cessation of
radiation the wind stops and the night is still.
[Sidenote: Prevailing winds.]
On the western portions of the Colorado the wind comes from the Pacific
across Southern California. The hot air from the desert goes up and
out over the Coast Range, reaching seaward. How far out it goes is
unknown, but when it has cooled off it descends and flows back toward
the land as the daily sea-breeze. It re-enters the desert through such
loop holes in the Coast Range as the San Gorgonio Pass--the old Puerta
de San Carlos--above Indio. The rush of it through that pass is quite
violent at times. For wind is very much like water and seeks the least
obstructed way. Its goal is usually the hottest and the lowest place
on the desert--such a place, for example, as Salton, though I am not
prepared to point out the exact spot on the desert that the winds
choose as a target. On the Mojave Desert at the north their action is
similar, though there they draw down from the Mount Whitney region as
well as from the Pacific.
[Sidenote: Wear of the winds.]
[Sidenote: Erosion of mountains.]
In open places these desert winds are sometimes terrific in force
though usually they are moderate and blow with steadiness from certain
directions. As you feel them softly blowing against your cheek it is
hard to imagine that they have any sharp edge to them. Yet about you
on every side is abundant evidence of their works. The sculptor’s
sand-blast works swifter but not surer. Granite and porphyry cannot
withstand them, and in time they even cut through the glassy surface
of lava. Their wear is not here nor there, but all over, everywhere.
The edge of the wind is always against the stone. Continually there is
the slow erosion of canyon, crag, and peak; forever there is a gnawing
at the bases and along the face-walls of the great sierras. Grain by
grain, the vast foundations, the beetling escarpments, the high domes
in air are crumbled away and drifted into the valleys. Nature heaved up
these mountains at one time to fulfil a purpose: she is now taking them
down to fulfil another purpose. If she has not water to work with here
as elsewhere she is not baffled of her purpose. Wind and sand answer
quite as well.
[Sidenote: Rock-cutting.]
[Sidenote: Fantastic forms.]
But the cutting of the wind is not always even or uniform, owing to the
inequalities in the fibre of rock; and often odd effects are produced
by the softer pieces of rock wearing away first and leaving the harder
section exposed to view. Frequently these remainders take on fantastic
shapes and are likened to things human, such as faces, heads, and
hands. In the San Gorgonio Pass the rock-cuttings are in parallel
lines, and occasionally a row of garnets in the rock will make the
jewel-pointed fingers of a hand protruding from the parent body.[3]
Again shafts of hard granite may make tall spires and turrets upon a
mountain peak, a vein of quartz may bulge out in a white or yellow or
rose-colored band; and a ridge of black lava, reaching down the side
of a foot-hill, may creep and heave like the backbone of an enormous
dragon.
[Sidenote: Wash-outs.]
[Sidenote: Sand-lines in caves.]
Perhaps the greatest erosion is in the passes through which the winds
rush into the desert. Here they not only eat into the ledges and cut
away the rock faces, but they make great wash-outs in the desert
itself. These trenches look in every respect as though caused by
water. In fact the effects of wind and water are often so inextricably
mixed that not even an expert geologist would be able to say where
the one leaves off and the other begins. The shallow caves of the
mountains--too high up for any wave action from sea or lake, and
too deep to be reached by rains--have all the rounded appearance of
water-worn receptacles. One can almost see the water-lines upon the
walls. But the sand-heaped floor suggests that the agent of erosion was
the wind.
[Sidenote: Cloud-bursts.]
[Sidenote: Canyon streams.]
Yes; there is some water on the deserts, some rainfall each year.
Even Sahara gets its occasional showers, and the Colorado and the
Mojave show many traces of the cloud-burst. The dark thunder-clouds
that occasionally gather over the desert seem at times to reserve all
their stores of rain for one place. The fall is usually short-lived
but violent; and its greatest force is always on the mountains. There
is no sod, no moss, to check or retard the flood; and the result is
a great rush of water to the low places. In the canyons the swollen
streams roll down bowlders that weigh tons, and in the ravines many a
huge barranca is formed in a single hour by these rushing waters. On
the lomas and sloping valleys they are not less destructive, running
in swift streams down the hollows, and whirling stones, sand, and torn
bushes into the old river-beds.
[Sidenote: Desert floods.]
[Sidenote: Power of water.]
In a very short time there is a great torrent pouring down the
valley--a torrent composed of water, sand, and gravel in about equal
parts. It is a yellow, thick stream that has nothing but disaster for
the man or beast that seeks to swim it. Many a life has been lost
there. The great onset of the water destroys anything like buoyancy,
and the tendency is to drag down and roll the swimmer like a bowlder.
Even the enormous strength of the grizzly bear has been known to fail
him in these desert rivers. They boil and seethe as though they were
hot; and they rush on against banks, ripping out the long roots of
mesquite, and swirling away tons of undermined gravel as though it were
only so much snow. At last after miles of this mill-racing the force
begins to diminish, the streams reach the flat lake-beds and spread
into broad, thin sheets; and soon they have totally vanished, leaving
scarce a rack behind.
[Sidenote: Water-pockets.]
[Sidenote: No running streams.]
The desert rainfall comes quickly and goes quickly. The sands drink it
up, and it sinks to the rock strata, where, following the ledges, it
is finally shelved into some gravel-bed. There, perhaps a hundred feet
under the sand, it slowly oozes away to the river or the Gulf. There
is none of it remains upon the surface except perhaps a pool caught
in a clay basin, or a catch of water in a rocky bowl of some canyon.
Occasionally one meets with a little stream where a fissure in the
rock and a pressure from below forces up some of the water; but these
springs are of very rare occurrence. And they always seem a little
strange. A brook that ran on the top of the ground would be an anomaly
here; and after one lives many months on the desert and returns to a
well-watered country, the last thing he becomes accustomed to is the
sight of running water.
[Sidenote: Oases in the waste.]
In every desert there are isolated places where water stands in
pools, fed by underground springs, where mesquite and palms grow, and
where there is a show of coarse grass over some acres. These are the
so-called oases in the waste that travellers have pictured as Gardens
of Paradise, and poets have used for centuries as illustrations of
happiness surrounded by despair. To tell the truth they are wretched
little mud-holes; and yet because of their few trees and their pockets
of yellow brackish water they have an appearance of unreality. They are
strange because bright-green foliage and moisture of any kind seem out
of place on the desert.
[Sidenote: Catch-basins.]
[Sidenote: Old sea-beds.]
Yet surely there was plenty of water here at one time. Everywhere you
meet with the dry lake-bed--its flat surface devoid of life and often
glimmering white with salt. These beds are no doubt of recent origin
geologically, and were never more than the catch-basins of surface
water; but long before ever they were brought forth the whole area
of the desert was under the sea. To-day one may find on the high
table-lands sea-shells in abundance. The petrified clams are precisely
like the live clams that one picks up on the western coast of Mexico.
The corals, barnacles, dried sponge forms, and cellular rocks do not
differ from those in the Gulf of California. The change from sea to
shore, and from shore to table-land and mountain, no doubt took place
very slowly. Just how many centuries ago who shall say? Geologists may
guess and laymen may doubt, but the Keeper of the Seals says nothing.
[Sidenote: Volcanic action.]
[Sidenote: Lava streams.]
Nor is it known just when the porphyry mountains were roasted to a
dark wine-red, and the foot-hills burnt to a terra-cotta orange. Fire
has been at work here as well as wind and water. The whole country has
a burnt and scorched look proceeding from something more fiery than
sunlight. Volcanoes have left their traces everywhere. You can still
see the streams of lava that have chilled as they ran. The blackened
cones with their craters exist; and about them, for many miles, there
are great lakes and streams of reddish-black lava, frozen in swirls and
pools, cracked like glass, broken into blocks like a ruined pavement.
Wherever you go on the desert you meet with chips and breaks of lava,
showing that at one time there must have been quantities of it belched
out of the volcanoes.
[Sidenote: Geological ages.]
[Sidenote: Kinds of rock.]
There were convulsions in those days when the sea washed close to the
bases of the mountains. Through the crevasses and fissures in the rocks
the water crept into the fires of the earth, and explosions--volcanic
eruptions--were the result. Wandering over these stony tracks you might
fancy that all strata and all geological ages were blown into discord
by those explosions. For here are many kinds of splintered and twisted
rocks--rocks aqueous and igneous, gritstones, conglomerates, shales,
slates, syenite, basalt. And everywhere the white coatings of carbonate
of lime that look as though they were run hot from a puddling furnace;
and the dust of sulphur, copper, and iron blown upon granite as though
oxidized by fire.
[Sidenote: Glaciers.]
[Sidenote: Land slips.]
The evidence for glaciers is not so convincing. There is no apparent
sign of an ice age. Occasionally one sees scratches upon mountain walls
that are suspicious, or heaps of sand and gravel that look as though
pushed into the small valleys by some huge force. And again there are
places on the Mojave where windrows of heavy bowlders are piled on
either side of mountain water-courses, looking as though ice may have
caused their peculiar placing. But there is no certainty about any of
these. Land slips may have made the windrows as easily as ice slips;
and water can heap mounds of sand and gravel as readily as glaciers.
One cannot trace the geological ages with such facility. Things
sometimes “just happen,” in spite of scientific theories.
[Sidenote: Movement of stones.]
[Sidenote: The talus.]
Besides, the movement of the stones into the valleys is going on
continuously, irrespective of glaciers. They are first broken from the
peaks by erosion, and then they fall into what is called a talus--a
great slope of stone blocks beginning half way down the mountain and
often reaching to the base or foot. Many of them, of course, are rolled
over steep declivities into the canyons and thence carried down by
flood waters; but the talus is the more uniform method for bowlders
reaching the plain.
[Sidenote: Stages of the talus.]
In the first stage of the talus the blocks are ragged-edged and as
large as a barrel. Nothing whatever grows upon the slope. It is as bare
as the side of a volcanic crater. And just as difficult to walk over.
The talus is added to at the top by the falling rock of the face-wall,
and it is losing at the bottom by the under blocks grinding away to
stone and gravel. The flattening out at the bottom, the breaking up
of the blocks, and the push-out of the mountain foot upon the plain
is the second stage of the talus. In almost all the large valleys of
the desert the depressed talus extends, sometimes miles in length, out
from the foot of the mountain range. When it finally slips down into
the valley and becomes a flat floor it has entered upon its third and
last stage. It is then the ordinary valley-bed covered with its cactus
and cut by its arroyos. Yet this valley-floor instead of being just
one thing is really many things--or rather made up of many different
materials and showing many different surfaces.
[Sidenote: Desert-floors.]
[Sidenote: Sandstone blocks.]
[Sidenote: Salt-beds.]
[Sidenote: Sand-beds.]
You may spend days and weeks studying the make-up of these
desert-floors. Beyond Yuma on the Colorado there are thousands of
acres of mosaic pavement, made from tiny blocks of jasper, carnelian,
agate--a pavement of pebbles so hard that a horse’s hoof will make
no impression upon it--wind-swept, clean, compact as though pressed
down by a roller. One can imagine it made by the winds that have cut
and drifted away the light sands and allowed the pebbles to settle
close together until they have become wedged in a solid surface. For
no known reason other portions of the desert are covered with blocks
of red-incrusted sandstone--the incrustation being only above the
sand-line. In the lake-beds there is usually a surface of fine silt.
It is not a hard surface though it often has a crust upon it that
a wild-cat can walk upon, but a horse or a man would pound through
as easily as through crusted snow. The salt-beds are of sporadic
appearance and hardly count as normal features of the desert. They
are often quite beautiful in appearance. The one on the Colorado
near Salton is hard as ice, white, and after sunset it often turns
blue, yellow, or crimson, dependent upon the sky overhead which it
reflects. Borax and gypsum-beds are even scarcer than the salt-beds.
They are also white and often very brilliant reflectors of the sky. The
sand-beds are, of course, more frequently met with than any others; and
yet your horse does not go knee-deep in sand for any great distance. It
is too light, and is drifted too easily by the winds. Bowlders, gravel,
and general mountain wash is the most common flooring of all.
[Sidenote: Mountain vegetation.]
[Sidenote: Withered grasses.]
The mountains whence all the wash comes, are mere ranges of rock. In
the canyons, where there is perhaps some underground water, there are
occasionally found trees and large bushes, and the very high sierras
have forests of pine belted about their tops; but usually the desert
ranges are barren. They never bore fruit. The washings from them are
grit and fry of rock but no vegetable mould. The black dirt that lies a
foot or more in depth upon the surface of the eastern prairies, showing
the many years accumulations of decayed grasses and weeds, is not known
anywhere on the desert. The slight vegetation that grows never has a
chance to turn into mould. And besides, nothing ever rots or decays in
these sands. Iron will not rust, nor tin tarnish, nor flesh mortify.
The grass and the shrub wither and are finally cut into pieces by
flying sands. Sometimes you may see small particles of grass or twigs
heaped about an ant-hill, or find them a part of a bird’s nest in a
cholla; but usually they turn to dry dust and blow with the wind--at
the wind’s will.
[Sidenote: Barren rock.]
[Sidenote: Mountain colors.]
The desert mountains gathered in clusters along the waste, how old and
wrinkled, how set and determined they look! Somehow they remind you of
a clinched hand with the knuckles turned skyward. They have strength
and bulk, the suggestion of quiescent force. Barren rock and nothing
more; but what could better epitomize power! The heave of the enormous
ridge, the loom of the domed top, the bulk and body of the whole are
colossal. Rising as they do from flat sands they give the impression
of things deep-based--veritable islands of porphyry bent upward from
a yellow sea. They are so weather-stained, so worn, that they are not
bright in coloring. Usually they assume a dull garnet-red, or the red
of peroxide of iron; but occasionally at sunset they warm in color and
look fire-red through the pink haze.
[Sidenote: Saw-toothed ridges.]
The more abrupt ranges that appear younger because of their saw-toothed
ridges and broken peaks, are often much finer in coloring. They have
needles that are lifted skyward like Moslem minarets or cathedral
spires; and at evening, if there is a yellow light, they shine like
brazen spear-points set against the sky. It is astonishing that dull
rock can disclose such marvellous coloring. The coloring is not local
in the rock, nor yet again entirely reflected. Desert atmosphere, with
which we shall have to reckon hereafter, has much to do with it.
[Sidenote: Seen from the peaks.]
[Sidenote: Sun-fire kingdom.]
And whether at sunset, at sunrise, or at midnight, how like
watch-towers these mountains stand above the waste! One can almost
fancy that behind each dome and rampart there are cloud-like
Genii--spirits of the desert--keeping guard over this kingdom of the
sun. And what a far-reaching kingdom they watch! Plain upon plain leads
up and out to the horizon--far as the eye can see--in undulations of
gray and gold; ridge upon ridge melts into the blue of the distant sky
in lines of lilac and purple; fold upon fold over the mesas the hot
air drops its veilings of opal and topaz. Yes; it is the kingdom of
sun-fire. For every color in the scale is attuned to the key of flame,
every air-wave comes with the breath of flame, every sunbeam falls as
a shaft of flame. There is no questioning who is sovereign in these
dominions.
FOOTNOTES:
[3] Professor Blake of the University of Arizona has called my
attention to this.