Archaeological Sites of the eastern Snake River Plain
chronology of the eastern Snake River Plain
first human beings to tap the resources of what we now call the
Snake River Plain likely were descendants of people who crossed
the Bering Strait land bridge; they arrived here some 11,000 B.P.
That date was obtained from cultural deposits in Owl Cave
(Wasden Site) just east of the INEEL. A date of 14,500 B.P. was obtained three decades ago
during the infancy of radiocarbon dating from deposits in Wilson
Butte Cave (see
Map), 200 km southwest of the INEEL (Gruhn 1965);
however, newer dating techniques applied to the same
deposits provided dates younger than 11,000 years B.P. (Meatte
1989). Other archaeological sites on the Plain, in caves and
lava tubes, along the shorelines of rivers and lakes, and in the
foothills, have established that humans have occupied the Snake
River Plain and its edges more or less continuously ever since.
Over 850 archaeological sites at the INEEL (see
a slow, steady increase in use of the area during that period
(R. Holmer, personal communication).
Palynological and archeological studies show that plant
species composition on the Snake River Plain has changed little
during the Holocene (the past 10,000 years) (Davis and Bright
1983, Davis et. al. 1986, Steadman et al. 1994), but the
altitudinal distributions and relative abundances of individual
species likely were different during the Altithermal, a period
of gradual warming and drying during the early to mid Holocene
Studies in the area indicate a peak in xeric conditions
between 8,200 and 6,700 B.P. (Beiswenger 1991);
however, warm and dry conditions apparently persisted on
the eastern Snake River Plain at least until 5,500 B.P. (Davis
A change in projectile point morphology around 7,500 B.P.
suggests a shift in hunting technology (see
Cultural Chronology) Another shift around 4,500 B.P. may have corresponded
with occupation of the area by migrants from the south following
the close of the Altithermal.
The widespread climatic shift to more arid conditions
during the early Holocene may have caused the earliest human
inhabitants of the Plain to follow the moist conditions to which
they were accustomed to higher latitudes, thus opening a niche
on or around the Plain for people migrating north from the
comparatively more arid conditions in the south
According to this hypothesis, the Plainís original
inhabitants were ancestors of the Plateau or Plains cultures to
the north, while sometime during or toward the close of the
Altithermal, ancestors of the present day Northern Shoshone and
Bannock (Northern Paiute) emigrated north from the Great Basin
and took up residence on the Snake River Plain (Holmer 1994).
Until the last decade this hypothesis had little support
from the archaeological record, but data from two recently
discovered sites are consistent with it.
A camp site at Dagger Falls on the Middle Fork of the
Salmon River shows Shoshonean cultural continuity from 4,000 B.P.
to historic times, and the sacred Wahmuza site on the Fort Hall
bottoms shows similar continuity from 2,000 B.P. (Torgler 1995,
The temporal, contextual, and artifactual overlap between
these two sites seems to confirm continuous Shoshonean presence
in southern Idaho since the close of the Altithermal.