3.5 Cultural Resources
sand dredging. At this site, five seismic survey lines were conducted approximately perpendicular to the
beach direction, and six survey lines were conducted parallel to the beach direction. A total of five
vibracores were collected, primarily in the eastern portion of the grid. The deepest core penetration was
10.6 feet, in the south-central portion of the grid.
Geoarchaeological Results
Two offshore archaeological sites are recorded near SO-6, along the margins of San Elijo Lagoon (Table
3.5-1, Sites 22 and 36). More than 100 artifacts have been recovered from these sites. Site 22 is located
in 3- to 26-foot deep water south of the lagoon entrance, and Site 36 is located in 39-foot deep water
north of the lagoon entrance.
The dredge area for SO-6 spans the northern edge of the offshore paleochannel of San Elijo Lagoon. The
side scan sonar data reveal an extensive rippled bedform, particularly in the south and eastern portion of
the grid, suggesting a surface sand cover in these regions. The sub-bottom profile data also suggest a
defined boundary between these two regions. Using the vibracore and sub-bottom data as a guide, a
geologic cross-section of SO-6 indicates a division between a shallow (5-foot) bedrock interface, with
overlying offshore sediments in the northern portion of the grid, and a paleochannel filled with a sequence
of sedimentary facies in the southern portion of the grid.
The potential for occurrence of archaeological sites at SO-6 varies with location within the grid. The
northern portion of the grid has a low probability for site occurrence since in that region offshore sediments
rest directly on bedrock. The southern portion of the grid has a higher probability for site occurrence since
in that region an intertidal-to-fluvial (pre-transgression to transgression) contact is present. The designated
sand source region within SO-6 is a high probabilityprehistoric site zone, since it is within the paleochannel,
along its northern margin and since it is close to a known offshore prehistoric artifact locality (Table 3.5-1,
Site 36).
Historical Results
One unidentified sonar target was detected just west of the proposed dredge area, but analysis of sonar
imaging suggests it is a sunken vessel. Two historic ships have been documented or reported to exist within
this area. Precise locations of shipwrecks are often notoriously inaccurate but, actual historic vessel
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