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

Figure H-5. Western Washington Chronological Sequence
Early Period
During the early Holocene (ca. 10,000 B.P.-5,000 B.P.), the region experienced a relatively
stable environment compared with the dynamic changes that occurred at the end of the
Pleistocene, albeit one warmer and drier than today’s climate. Relative sea level fluctuation was
the most significant long-term environmental perturbation; rising global sea level during this
time submerged the marine shorelines that may have been occupied during earlier times. Brush
fires and forest fires were common during periods of summer drought and caused short-term,
localized environmental changes in the forest parkland habitats. By the end of this period, the
post-glacial parkland/forest mosaic across much of Western Washington evolved into a closed
canopy forest. The distribution of important subsistence resources such as deer and elk changed,
and human land use patterns changed as well. Prior to the mid-Holocene closing of the forest
canopy, terrestrial mammals were a subsistence resource widely available throughout the glacial
drift plains. The first well-dated evidence of generalized, marine littoral subsistence first appears
in the archaeological record of the Gulf of Georgia region during this period as well.
Humans accommodated environmental changes during the Early Period by utilizing a wider
range of subsistence resources. Increasingly complex patterns of land use resulted in additional
archaeological site types, more elaborate toolkits, and more intensive use of the marine shoreline
and anadromous fish runs that grew more productive as the pace of rising sea level slowed. The
archaeological record of residential camps is still very sparse during this period, probably due in
Northern Border Activities H-60 July 2012