Geoscience Reference
In-Depth Information
the Central Valley was transformed into an inland sea. h ese earlier l oods
would have destroyed any human settlements in the Central Valley. For this
reason, it is likely that the native populations used the Central Valley only
seasonally and not as a location of permanent settlement.
mound builders of the san francisco bay
Downstream of the Sierra Nevada and the Central Valley, rivers draining
these regions l ow into San Francisco Bay before reaching the Pacii c Ocean.
Clues to the climate of the Bay Area during the Neoglacial are found in
sediment accumulation beneath the bay waters as well as in archaeological
investigations of the shell mound villages along the coast.
h e remains of several hundred mysterious mounds that once served
as dwellings for a population of hunter-gatherers along the shores of San
Francisco Bay have proven to be valuable—if unlikely—sources of informa-
tion about Neoglacial climate in the West. Archaeologists discovered these
mounds in the early twentieth century, along with their most unusual fea-
ture: they were composed almost entirely of shelli sh remains.
Unlike mounds found elsewhere in North America, which were primarily
specialized burial sites, the Bay Area mounds were large enough to suggest
that they functioned as residences. Because they were created through the
daily accumulation of household debris, the mounds contain a wealth of
materials for reconstructing the environment and the climate, including the
remains of i sh and shelli sh from the bay, the bones of terrestrial animals,
and a wide array of foraged remains.
But before the signii cance of the mounds could be understood, archae-
ologists in the early twentieth century were forced into a race with urban
development. One of the leading archaeologists of the time, Nels Nelson,
worked heroically to map over 425 of the mounds, but he noted as early as
1909 that most of the larger mounds had been disturbed. Archaeological
i eldwork in the Bay Area became largely a salvage operation, with scientists
frantically digging ahead of the bulldozers that were poised to level the sites
for new roads, parking lots, and businesses. During these rushed excava-
tions, there was barely time to catalog artifacts before whisking them away
for storage in museums. Except for those fragments (and a few shell mounds
protected intact within state parks), the archaeological record of the earliest
human inhabitants of the San Francisco Bay region has been largely erased.
