Appendix H - Historical Archaeological and ... - CBP.gov

climate, which was at a peak of warmth and aridity in the millennia following retreat of
continental glaciations, continued to be warmer than today.
By about 8,000 years ago, however, a trend towards cooler and wetter conditions in the northern
Plateau allowed an expansion of mountain forests into lower elevations and shrub-steppe
vegetation to replace the grasslands that covered the Columbia Basin. The relatively cooler and
wetter seasonal conditions that intensified into the mid-Holocene expanded ungulate habitat and
promoted growth of root plants that soon became economically important. Salmon habitat
improved as well once the water temperature of the Columbia and Fraser River systems cooled
and sediment load from channel down-cutting decreased. Campsites situated near these
resources and the tools for efficient harvest and processing appear in the archaeological record
during this time.
The late Holocene saw further changes in land use patterns and greater dependence upon
particular subsistence resources and food storage strategies. In general, the climate shifted
towards the same cooler, wetter Neoglacial regime seen across much of northwestern North
America; brief periods within the latter half of the Holocene, however, brought occasions of
drought, flooding, and warming. Parallel to these changes were shifts from settlements with
fewer but larger semi-subterranean houses to village sites with numerous but smaller pithouses in
some regions, and an opposite pattern in others. One broad-scale trend during this period was a
growing dependence upon storage as a mechanism to offset fluctuations in seasonal resource
availability and inter-annual productivity. Increasingly intensified use of salmon occurred along
the Columbia River and its tributaries below Kettle Falls as ungulate habitat shrank during the
late Holocene. Labor-intensive resources such as freshwater mussels and edible roots increase in
importance as well, especially in places within this region that did not provide access to salmon.
Similar to the rest of North America, land use patterns dramatically shifted as a result of initial
Euroamerican contact and disease epidemics at the end of the eighteenth century. Like those
epidemics, the adoption of horses as a means of transport and trade in the interior Northwest
preceded actual contact with Euroamericans by several years and had profound implications on
Native American land use.
Site Types
The archaeological record of the Plateau region along the U.S.-Canada border is characterized by
a variety of artifacts and features that reflect broad-scale changes in Native American land use
from the end of the Pleistocene to first encounters with Euroamerican explorers in the late 1700s.
These materials and deposits are classified into assemblages to infer chronological sequences and
past lifeways. This brief overview describes the kinds of pre-contact Native American
archaeological deposits found in Eastern Washington and Idaho within the PEIS zone. Artifacts
and assemblages characteristic of particular chronological periods are further described in the
subsequent section.
Residential sites, often in the form of one or more semi-subterranean house pits, are more
common in the archaeological record of the Eastern Washington Plateau than that of Western
Washington. Sites pre-dating the mid-Holocene are inferred to be habitations based on the
composition of their lithic and faunal assemblages and presence of fire-modified and occasional
features (Chatters and Pokotylo, 1998). The first house pit sites to appear across the region by
about 5,000 years ago were near the ecotones between steppe and forests and contained house
Northern Border Activities H-63 July 2012