Archaeological Investigations at Montaña de Oro State Park,

San Luis Obispo County, California

Faunal Remains

The excavation strategy employed at CA-SLO-9 emphasized the recovery of faunal remains in order to assess the prevailing models of regional prehistory that stress prehistoric diet and faunal exploitation. The faunal remains are presented according to the following broad taxonomic categories: mammals and birds, fish, and invertebrates.

Fishhook recovered from CA-SLO-9

Mammal & Bird Remains

In order to generate a meaningful sample of mammal and bird remains, most of the excavation involved relatively large (1 x 2 m) units, from which soils were dry-screened through 3mm (1/8 inch) mesh in the field.  For the purposes of dietary reconstruction, minimum number of individuals (MNIs) were calculated for each 10 cm level per unit level. The amount of edible flesh represented by each MNI was calculated via reference to taxon-specific mean meat yields. A total of 2332 specimens were identified. Of these, 500 bones were identified to the family level or better. Unfortunately, the site yielded many bones from small burrowing animals, and as a result, the single most abundant animal identified to species was the pocket gopher (Thomomys bottae), which was represented by 282 specimens or 56.4% of the identifiable collection. 

Isolating the prehistoric assemblage, the collection was dominated by rabbit (Sylvilagus audubonii, Sylvilagus bachmani and Sylvilagus sp. combined; NISP = 37, 27.1%; MNI = 29, 25.9%), cormorant (Phalarocorax sp.; NISP = 30, 21.9%; MNI = 26, 23.2%), sea otter (Enhydra lutris; NISP = 18, 13.1%; MNI = 18, 16.1%), and dog/coyote (Canis sp.; NISP = 14, 10.2%; MNI = 12, 10.7%).  Looking at broader classes, the collection was dominated by terrestrial mammals (NISP = 74, 54%; MNI = 55, 49.1%), birds (NISP = 41, 29.9%; MNI = 35, 31.3%) and marine mammals (NISP = 22, 16.1%; MNI = 22, 19.6%). The following table represents a summary of identified mammal, bird, and reptile remains from CA-SLO-9.

Fish Remains

All fish bone recovered from CA-SLO-9 was submitted to Dr. Ken Gobalet for taxonomic identifications. Dr. Gobalet used a reference collection housed at the Department of Biology, California State University, Bakersfield to aid in identifying elements to the lowest possible taxon. A minimum of 2260 fish elements was recovered, including a total of 670 specimens from all proveniences identified to the family level or better. Ignoring both mesh size and recovery volume and looking only at the relative percentages of the total number of identifiable specimens, the overall sample was dominated by rockfish (NISP=292; 44%), and cabezon (NISP=192; 29%), followed by senorita (NISP=46; 7%), surfperch (NISP=40; 6%), and pricklebacks/monkeyface (NISP=33; 5%). Cabezon and rockfish also dominate the assemblage when ranked by MNI (combined=295; 78%) and weight (combined=70.16; 90%). When considering recovery techniques, cabezon followed by rockfish dominate the 1/4" (6mm) mesh while rockfish dominate the control unit with cabezon and senorita following. The density of identifiable elements recovered from the control unit was 151.2 elements/m3 and 820.8 elements/m3 for all specimens. The table below illustrates a summary of the fish remains recovered from CA-SLO-9.

Invertebrate Remains

Using reference collections at the Cal Poly Archaeology Laboratory, April Matthews, Justin Housman, and Brian Codding completed identification of invertebrate remains. Ms. Matthews examined a sample of the large shell fragments collected in 2004 to develop a complete species list. Ms. Matthews, Mr. Housman and Mr. Codding then examined 100% of the shell fragments retained in the 3mm mesh from the two column samples. After identification, total weights per level per species were recorded to determine species composition and proportion. The total volume examined was 0.64m3. The relative importance of shellfish taxa was evaluated by conversion of shell weights into meat weights through the use of taxon-specific meat: shell ratios. In addition to basic identifications, the remains of mussel and abalone were subjected to specialized analyses. Maximum length was recorded for all complete and nearly complete mussel shells from Unit 4 using the size template developed by White (1989), which allow for the size of incomplete specimens to be estimated. A total of 27 invertebrate species was identified representing 10 groups: abalones, mussels, clams, turban snails, limpets, keyhole limpets, chitons, miscellaneous snails, barnacles, urchins and crabs. Many of these species were represented by whole, or nearly whole shells recovered from macro-samples and were insignificant in the deposit in terms of overall proportion as represented in the column samples. The two 20 x 20 cm column samples from CA-SLO-9 totaled a combined volume of 0.64 m3 and produced 2167.83 g of shell representing 27 taxa identified to the genus level or better. When compared with one another, the column samples were statistically similar (t-test, P > 0.05), indicating a rather homogenous midden. For comparison of the relative abundances, unidentified shell fragments were dropped and specimen weights were grouped into the ten classes mentioned above. Further, shell weights were multiplied by the appropriate meat : weight conversion ratio so that the relative abundances would be indicative of actual meat yields rather than shell weight. The results indicate that over 70% of the invertebrate taxa exploited at SLO-9 were either mussel, abalone, or urchin; with a primary reliance on mussel (32.68%) and abalone (31.92%), followed by urchin (11.79%), barnacle (8.45%), turban snail (6.79%) and chiton (4.26%).

Invertebrate species represented at CA-SLO-9.

Contribution of economically significant invertebrate taxa at CA-SLO-9

Non-Bead Shell Artifacts & Bone Tools

A total of nine fishhooks were recovered, along with one fishhook blank and a nearly complete H. rufescens shell with its holes plugged with asphaltum. Five of the hooks were made  from Mytilus californianus and four were from Haliotis sp. Although only one specimen was complete, all appear to represent the “C-shaped” or circular variety. While the single-piece circular shell fishhooks are certainly older in other regions of California, they are not common in Middle Period deposits in San Luis Obispo County. The large number found at SLO-9 may represent the artifacts emergence as the dominant fishing technology along the San Luis Obispo coast during the Middle/Late Transition.     

Bone tools are a problematic class on the central coast because specimens are frequently small and fragmented. Classification of bone tools in California is still dependent on typological nomenclature that is largely functional. Two fragmented awl tips were recovered from SLO-9; they exhibit the characteristic slender, sharp points, or the outline thereof before breakage. Another specimen, although complete, could not be assigned a more exact designation than bi-pointed object. This specimen was too robust to be an awl and too asymmetrical to be a gorge. The other two examples of worked bone from SLO-9 were too fragmentary to be classified.

Non-bead shell artifacts and bone tools from CA-SLO-9.

References Cited

Dietz, S. A., W. R. Hildebrandt, and T. L. Jones  1988 Archaeological Investigations at Elkhorn Slough: CA-MNT-229, A Middle Period Site on the central California Coast. Papers in Northern California Anthropology No. 3. Berkeley, California.

 

Rick, T. C., R. L. Vellanoweth, J. M. Erlandson and D. J. Kennett 2002 On the Antiquity of the Single-Piece Shell Fishhook: AMS Radiocarbon Evidence from the Southern California Coast. In Journal of Archaeological Science 29:933–942.

 

White, G. G. 1989 A Report of Archaeological Investigations at Eleven Native American Coastal Sites, MacKerricher State Park, Mendocino County, California. Report prepared for the California Department of Parks and Recreation, Sacramento. Copies available from Northwest Information Center, Sonoma State University, Rohnert Park.