Considered as a tribal habitat, Seriland comprises four subdivisions
of measurably distinct character, viz., (1) the broad desert bounding
the territory on the east; (2) the mountainous zone of Sierra Seri;
(3) Tiburon island and the neighboring islets; and (4) the navigable
straits and bays contiguous to island and mainland.
1. So far as its marginal portions are concerned, Desierto Encinas is
a typical valley of the Sonoran province, sparsely dotted with vital
colonies of the prevailing type and variegated by the exceptionally
luxuriant mesquite forests of the Bacuache and Sonora fans; but the
interior of the valley is rendered distinct by the fact that it lies
near, if not below, the level of the sea.[11] The central feature
is Playa Noriega—a film of brackish water for a few days after each
considerable semiannual freshet, a sheet of saline mud for a few weeks
later, and for the greater part of the year a salt-crusted sherd 20
square miles in area, level as a floor and unimpressionable as a brick
pavement. The playa is rimmed by dunes 10 to 40 feet in height, and
about these and along the arroyos which occasionally break into it
there is some aggregation of salt-enduring shrubs, evidently sustained
in part by the semiannual freshet with its meager vapors and fogs.
Outside this rim the surface is exceptionally broken; low dunes and
irregularly wandering banks of soft and dust fine sand are interspersed
with meandering salt flats much like the central playa, ranging from a
few feet in width and a few yards in length up to mappable dimensions,
as in the lesser playa lying east of the great one; and many of the
dustbanks are honeycombed with squirrel burrows. This annulus of broken
surface is narrow on the west, soon passing into okatilla scrub and
then into the saguesa forests of the eastern base of Sierra Seri; on
the east it is miles in breadth, passing gradually into the normal
Sonoran plain; on the south it widens still farther, stretching all
the way to Arenales de Gil and Pozo Escalante, and merging into the
playa-like mud-flats bordering Laguna la Cruz, into which the gulf
waters are sometimes forced by southwesterly gales at high spring
tides. Throughout this portion of the desert, marine shells are
scattered over the playa-like flats or lodged in the adjacent banks,
sometimes in great beds; the vegetation is scantier than usual and
largely of salt-loving habit; the mud-flats are usually coated with
saline and alkaline crusts, while the dunes are soft and fluffy, and
expand into broad belts perforated with the tunnels of the surprisingly
abundant rodents. Across this plain of bitter sand-dust lie the two
hard land routes to Seriland—the supposed Escalante route of 1700, down
the fan of Rio Bacuache and thence by Barranca Salina; and the Encinas
route, down the northern border of the Rio Sonora fan and thence by
Pozo Escalante to the shores of Bahia Kino.[12]
[11] The expedition of 1895, during which Seriland was surveyed, was
not provided with apparatus for accurate vertical measurement, and
hence altitudes were only approximately determined. The determinations
by Mr Johnson, who executed the topographic surveys, indicated that
even the lowest part of the valley is somewhat above sea-level; but
other facts indicate that it actually lies below the level of the
waters of the gulf, and forms a miniature homologue of Colorado desert
(in southern California): in the first place the central playa, which
is undoubtedly flooded occasionally if not semiannually, does not
embouch into, and has no channels extending toward, the sea; in the
second place it is highly saline; again, the alluvial fans of Rio
Bacuache and (especially) of Rio Sonora are so placed as to intercept
and dam the trough occupied by Laguna la Cruz in its southern portion,
and Playa Noriega in its northern portion; concordantly, the detail
configuration of the coast indicates marine transgression, apparently
due to secular subsidence of the land—though the abundant marine shells
of recent species toward the valley-bottom attest recent displacement
of the sea. On the whole, the facts seem to indicate that, during
recent geologic times, the lower portion of this valley was a shallow
gulf extending northward (and probably also southward) from the eastern
limit of Bahia Kino; that the importation and deposition of sediment,
chiefly by Rio Sonora, outran the secular subsidence of the land so
far as to displace the waters of the gulf in its central portion and
to separate the northern arm from the sea; and that the waters of this
northern arm were subsequently evaporated, disappearing finally in the
central playa in which local inflow and evaporation are balanced by the
usual mechanism of interior basins.
[12] Both the routes were traversed by the expedition of 1895, the
former from the headwaters of Rio Bacuache to the upper portion of its
alluvial fan, and then from the abandoned Rancho Libertad on the lower
portion of the fan across Desierto Encinas by way of Barranca Salina.
In the northern crossing a light vehicle (the first to traverse this
portion of the desert), drawn by four horses and aided by several
horsemen, was taken from Rancho Libertad across the northern portion of
Playa Noriega and thence up Arroyo Mitchell to a point midway between
Barranca Salina and Johnson peak, and was brought back over the same
route. The Encinas trail from Rancho San Francisco de Costa Rica was
traversed four times each way by the same outfit, and once each way by
the running gear of a heavy wagon carrying the rude craft (about 1,000
pounds in weight) in which the Seri waters were navigated, this vehicle
being drawn by 8 to 12 horses, frequently changed. Typical aspects of
both routes are shown in plate III, the upper figure representing the
Encinas trail and the lower a distant view of Sierra Seri, taken from
Playa Noriega, in the depths of Desierto Encinas.
Desierto Encinas is an impossible human habitat in any proper sense; it
is merely a broad and hardly passable boundary between habitats. The
hardy stock of the frontier ranchos, pasturing partly on the thorny
fruit of the cholla, push far out on the plains, and are sometimes
watered for short periods, under strong guards of heavily armed
vaqueros, at Barranca Salina; yet the greater part of the expanse is
trodden only by the Seri. Two or three ruined frames of Seri jacales
and a few graves crown the low knoll near Pozo Escalante, and there
are one or two house remnants near Barranca Salina; these are notable
not only as the easternmost remaining outposts of Seri occupancy, but
because they represent the only known instances in all Seriland of the
erection of even temporary houses adjacent to water. Distinct paths,
trodden deep by bare Seri feet, radiate from both waters toward the
Seriland interior, but no traceable trails extend eastward.
The southern limit of Desierto Encinas is marked either by the broad
mud-flats opening into Laguna la Cruz or by the coast of the gulf,
the coast cutting the lower portions of the plain being accentuated
by a sand-bank 30 or 40 feet high, against which the surf thunders
in nearly continuous roar, audible halfway or all the way to Pozo
Escalante. A Seri trail skirts the crest of this bank, sending
occasional branches into the interior. At Punta Antigualla the bank
expands and rises into a great mammillated shell-mound nearly 100
feet high, with several of the cusps occupied by more or less ruined
jacales; and occasionally occupied houses occur midway thence to the
southernmost point of Sierra Seri, and again at the base of the first
spur east of Punta Ygnacio. Beyond Punta Antigualla the sweep of the
waves is stronger than in Bahia Kino, and the coastal sand-bank is
generally higher. Between the rocky buttresses of Punta Ygnacio and
the next spur eastward the sand-ridge rises fully 50 feet above mean
low tide, and here, as elsewhere, its verge is protected by a fog-fed
chaparral thicket with occasional clumps of okatilla and other cacti.
Behind the coast barrier lie lagoon-like basins, generally dry and
floored with saline silt-beds, though sometimes occupied by briny
pools formed through seepage during southwesterly gales; and there are
physiographic indications that the northwestward extension of Laguna la
Cruz formerly stretched some miles farther than now and lay in the rear
of Punta Antigualla in such wise as to form a source of supply of the
clam-shells of which the eminence is built.
[Illustration: BUREAU OF AMERICAN ETHNOLOGY