Olivella Shell Beads At Cueva Santa Rita
Molly Sells
12/5/13
Environmental Archaeology
Introduction
This paper discusses shell beads found at the Cueva Santa Rita site in
Baja California Sur, Mexico. The shell genus in topic is Olivella. The Olivella shell
beads are important to the archaeological record because they show trade
networks throughout the Americas. The shells have been collected for beads
along the Pacific Coast since early Holocene times and were traded for hundreds
of miles inland. Olivella shells can be found in the Pacific, Gulf of California, or
Gulf of Mexico. Olivella, the common name of dwarf olives, is a genus of small
predatory sea snails that are in the family of Olivellidea. Adults in the Olivella
species are usually very small, hence the genus name of “dwarf olive”.
There were two species of Olivella genus beads found at Cueva Santa
Rita. They were Olivella biplicata and Olivella Dama. Olivella biplicata, also
known as “purple olive”, has a purple coloration to it, even when worn. It prefers
the colder waters of the pacific. They are found from the bottom of Alaska to the
tip of Baja California Sur. They prefer bottoms of sandy lagoons and bays at
about 50 meters depth. Olivella dama prefers warmer gulf waters of Baja
California and lives in shallow waters and sandpits. Olivella biplicata has a
bulging silhouette while Olivella dama has a torpedo silhouette. Olivella biplicata
and Olivella dama are some of the most commonly found shells found in
California and the Great Basin.
Study Site
Cueva Santa Rita is a rock shelter located in Baja California Sur, Mexico.
It is part of the Sierra de la Giganta, a mountain range that runs along the east
coast of the peninsula. It was inhabited by the Guaycura peoples. Jesuit
Missionaries recounted that they had larger social groups with considerable ingroup diversity. The shelter itself is wider than it is deep, with it being 50 meters
in length. The shelter was excavated in three 2x2 meter units and three 1x1
meter units in a discontinuous trench pattern. Shell beads were recovered from
bulk microbotanical samples that were processed in the lab (Henrickson, 2013).
Figure 1; Map of Baja
California Sur. This shows
the location of Cueva Santa
Rita in relation to the Sierra
de la Giganta. It also pictures
the location of the Guaycura
people (Henrickson, 2013).
Features of Olivella
Presented here the terms pertaining to parts of the Olivella shell that were
utilized in bead manufacture (Bennyhoff and Hughes, 1987).
Figure 3; landmarks and loci of Olivella
Shell
Figure 2; landmarks and loci of Olivella
Shell
Methods
Bead types were identified using the metric and morphological criteria
defined by Bennyhoff and Hughes. I oriented the beads according to their
standard orientation. A standard orientation generally means that the beads are
oriented spire up and the canal down. Shelves are normally at the top and, callus
remnants are at the right side (Bennyhoff and Hughes, 1987). Measurements
were taken of the diameter, length, and aperture length using a caliper in
millimeters (mm). I also looked at the nature of the opening to determine if it was
horizontal or oblique and whether or not the beads had been fire treated. Fire
treatment could have made the beads easier to work with when grinding of
breaking. Various colors are the result of different stages of heating. Overheating
results in a gray to black color, while no heat treatment resulted in a white or
natural color. Many of the beads at Cueva Santa Rita were unbleached finished
beads (Henrickson, 2013). Beads were then assigned to a type and class if they
met the criteria listed in Bennyhoff and Hughes typology for size and overall
morphological characteristics. If they did not match each of the of the
measurements, another type was sought until a match was made (Hartzel,1991).
Overall, this was a very straightforward process.
Id Number
Class
Diameter
Length
Aperture
Length
Bleached
Nature Of
Opening
CSR#2407
spire lopped
bead(A1)
6.32
13.34
1.25
yes
horizontal
CSR#2408
end ground
bead (B2)
8.54
17.7
1.92
yes
horizontal
CSR#2409
oblique spire
lopped (A2)
4.82
8.09
2.81
yes
oblique
CRS#2410
spire lopped
bead (A1)
5.06
10.62
1.34
yes
horizontal
CSR#2411
double oblique
barrel bead
2.47
3.26
1.2
no
oblique
Table 1. This is a representation of the measurements taken of the 5 shells in my
sample from CSR.
Description of Beads
James Bennyhoff and Richard Hughes established a classification system
of Olivella shell beads for California and the Western Great Basin. This work is,
as the authors claim, a “more coherent and sensitive shell bead typology”. The
Olivella beads are classified into 45 types and the work includes descriptions,
measurements, and temporal significance of each type (Dahdul, 2002).
Within my sample size, I found spire lopped beads, end ground beads,
double oblique barrel beads, and oblique spire lopped beads. Spire lopped beads
are defined as a nearly complete shell with on the spire removed perpendicular
to the body axis (figure 4; Bennyhoff & Hughes, 1987). The spire can be broken
off, ground off, or naturally worn. Some of the outer lip may be ground off to
facilitate stringing. Oblique spire lopped beads are describes as having the spire
ground off diagonally (figure 5; Bennyhoff & Hughes, 1987). End ground beads
are describes as having the canal and spire end removed by grinding (figure 6;
Bennyhoff & Hughes, 1987). The oblique spire lopped bead is a shell that has the
spire removed at an angle. All of the Oblique Spire-lopped specimens are of the
A2a class (Henrickson, 2013). The double oblique bead had the distal end
ground parallel to the proximal end (figure 7; Bennyhoff & Hughes, 1987).
Results
There were only five beads that were analyzed and categorized in this
research study. Olivella shells were found in all levels and units of Cueva Santa
Rita that can indicate that and they were long-term trade networks. In a larger
study that Celeste Henrickson did, she found that there were more Olivella
biplicata shells than Olivella dama shells. This can indicate that there was a
preference in Olivella biplicata or an avoidance of the gulf coast (Henrickson,
2013).
The way some beads were ground can also indicate different stringing
methods and arrangements. If the opening of the shell has a notch or an oblique
wear pattern, it can show that they beads were strung in a herringbone style or
worn around the neck or ankle. Side grinding usually results in a herringbone
pattern when strung. It shows the pattern of movement the bead had against a
particular surface. All beads were identifiable despite the chips and other use
ware. My findings did not change any of her data or findings (Bennyhoff and
Hughes, 1987).
Conclusion
A review of the project documents provided a detailed description of the
site, cultures, excavation methods, and bead manufacture. I was able to analyze
five shell beads and categorize them into types and class according the criteria
listed in the Bennyhoff and Hughes shell bead guide. The sample size I had was
not sufficient enough to come to any new conclusions from Celeste Henrickson’s
previous research on Olivella shells at Cueva Santa Rita.
Figure 4; Simple Spire Lopped
beads (A1)
Figure 5; Oblique Spire Lopped beads (A2)
Figure 6; End-ground beads (B2)
Figure 7; Double-oblique barrel bead
Literature Cited
Bennyhoff, James A., and Robert F. Heizer
1987 Shell Bead and Ornament Exchange Networks between California and
the Western Great basin. American Museum of Natural History Anthropological
Papers 64(2)
Dahdul, Mariam
2002 Beads and Pendants from the Coachella Valley, Southern California.
PCAS Quarterly, 38(2&3)
Hartzel, Leslie L.
1991 Archaeological Evidence for Stages of Manufacture of Olivella Shell
Beads in California, Journal of California and Great Basin Anthropology
Henrickson, Celeste
2013. Olivella Shell Bead Production at Cueva Santa Rita in south-central
Baja California Sur, Mexico: An Ethnohistoric and Archaeological study of
manufacture and significance Unpublished Ph.D dissertation, University of
California, Berkeley.