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Cogged Stones (California)

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  • Cogged Stones (California)

    California Cogged Stones
    Article and Photos by Devlin Gandy, G.I.R.S. Member


    Appearing en masse for over 2,000 years—then abruptly disappearing, leaving in their wake no clues as to their purpose or meaning—southern California's cogged stones represent a great unknown in California prehistory. Their localized range, lack of similarity to anything else, and sheer numbers leave one a bit bewildered as to their purpose.


    The modern discovery of cogged stones began sometime in the late 1800s. As fanning expanded in southern California's Orange County, so did archeological discoveries. Originally, it seems, they were largely overlooked. But by the 1930s they had been found in enough quantities in such a small area as to capture some of the public's attention. Beginning with J.W. Winterbourne's Orange County excavations in the late 1930s, followed by Herman Strandt and H. Heizer in the 1940s and 1950s, cogged stones received a great deal more attention. One time State Senator and Mayor of Riverside, Samuel Cary Evans, had a collection of them and compiled a now-lost list of some thirty possible uses of cogged stones, which included stone machinery and oil burners. To this day, there is still much uncertainty about what cogged stones are, though recent ethnographic evidence may offers some clues.


    Cogged stones are simply that, cog shaped stones. They come in a great many varieties but are essentially stone discoidals with "ribs" or "cogs" fashioned onto or into their sides. These cogs range in number from 1 to 22, with most having 10 to 17 (Jeffrey S. Couch 2009). Cogged stones occur in both perforated and non-perforated forms, convex and concave forms, and in sizes ranging from an inch to more than six inches. There are seven styles which are rooted in two classes: Oblique cogged stones and right cogged stones. The distinction between these two is apparent when being viewed laterally. An oblique cogged stone's sides are beveled—think trapezoid. Right cogged stones, on the other hand, have even sides, which are more or less perpendicular to the planes of the stone's face—they look rectangular. Currently, thanks to the efforts of Hal Eberhart, Susan Underbrink, and Henry Koerper, cogged stones are placed into a taxonomy which breaks them down into seven types. These are: beveled, land and groove, intermediate, fish vertebra, seastar, truncated, and ovoid. These type distinctions are based on basic aspects of their physical appearance.

    As a whole, cogged stones show no utilitarian wear, and many are made out of lithic materials not valued for their durability. Interestingly, when Cogged Stones broke in antiquity—either in late manufacture or through use—they were carefully repaired with asphaltum. Pleistocene discoidals, an object found regularly with cogged stones and considered to be the cogged stone's closest cousin, show no such signs of care. Often, a discoidal's breaks are polished down leaving the stone asymmetrical. Asymmetry is not a common feature in cogged stones.

    Cogged stones were made from a range of materials including red ochre, steatite, tonolite, rhyolite, diorite, talc schist, calcium carbonate concretions, sandstone, siltstone, limestone, andesite, dactite, dolerite, pumice, basalt, and granite (Eberhart 1961, Underbrink 2006). Recent studies seem to indicate that the choice of stone was significant. It has been noted recently by Jeffrey S. Couch, Joanne S. Couch, and Nancy Anastasia Wiley, that cogged stones coming from the Cogged Stone Site (ORA-83) are made of different materials than its sister site, the Irvine Site (ORA-64), even though both localities had ample access to the same materials. It appears that they chose to have distinct materials with which to fashion the artifacts that were to become the hallmarks of their sites during the same time period. It is therefore interpreted that specific stone types had tribal/clan affiliation (Couch, Couch, and Wiley 2009). More work needs to be done on this matter, but it is a very intriguing concept.


    Dating cogged stones has been relatively difficult as most have been found in heavily plowed fields. Only a few of those found in situ are datable. Known dates and estimates place their appearance during the Early Milling Stone Horizon, some 7,500 years ago. Some 2,500 years later they disappear abruptly (Eberhart 1961 and Koerper 2006). Their range is centered along the Santa Ana River drainage in southern California's Orange and Riverside Counties. This extremely small geographic area contributes to their peculiarity. Though limited in range, some sites, like Bolsa Chica in Orange County, have revealed over 1,000 cogged stones in a few acres. On occasion, they have been found some distance from the Santa Ana River, known from isolated examples in Ventura and Los Angeles Counties, and as far east as Chandler, in south central Arizona. It is uncertain if the isolated cogged stones are from the Santa Ana River basin as well, but many of the known examples are made of comparable rock types. This being said, it is believed that the migration of the cogged stones shows cultural affiliation between these areas—an affiliation which is difficult to accurately know, compare, or state because we don't know who those people were. Historically, the Gabrielino, Luisa, and Cahuilla occupied the areas in which cogged stones are most commonly found, but they are part of the Uto-Aztecan linguistic group, a group which entered California roughly at the same time cogged stones disappear from the archeological record. It is therefore highly unlikely that their culture is responsible for cogged stones.

    The time period in which cogged stones appear was far separated from the arrival of the Europeans and even the tribes present when Europeans arrived. It was a period of innovation and artistry along the California Coast some 7,000 years ago (Eberhart 1961 and Koerper 2006) known as the Milling Stone Horizon. It is named precisely for that, the ubiquitous presence of milling stones in the sites. This Horizon is further classified into three subsets: Early, Middle, and Late. These subsets span from 7,000 to 4,000 B.P., and cogged stones appear in the Early period and disappear by the Late period. Their appearance in the Early period is especially interesting in that the Cogged Stone is the most significant aspect of the material culture which designates this period; all other aspects are commonalities throughout other phases.

    The Milling Stone Horizon was one of climate change and was marked with cultural migrations throughout the region. In regards to the Santa Ana River and surrounding land, weather patterns were changing and plants from the north were encroaching south as Uto-Aztecan tribes began to arrive from Mexico. By the late period they began to occupy lands that were presumably owned by tribes related the Hokan linguistic group (Shipley 1978). The peoples who made the Santa Ana River area their home and created the cogged stones were presumably uprooted and/or migrated at the end of this period. Based on the presumption that they were part of the Hokan linguistic group, we can look at tribes like the Chumash to the north and the Yuman to the south, and we find that they also have cogged stones present in Milling Stone sites. It seems plausible that cogged stones were part of a culture that was centered along the Santa Ana River, but spread across a much larger area than is currently known. Isolated finds in sites which historically were home to tribes of the Hokan linguistic group bolster this idea, and it seems likely that the Chumash and Yuman, though not historically makers of cogged stones, are the descendents of the culture which made them.


    As of now, there is no single answer as to what cogged stones were made for. Some of the earliest ideas put forth were based on the presumption that they were utilitarian objects such as net weights, oil burners, nut grinders, mace heads, or cogs for stone machines. We now believe with some certainty that they were not utilitarian.

    The current view holds them to be ceremonial objects, but their meaning and symbolism are open for debate. One of the earliest ideas was that they represented sea life. From this perspective, some represent starfish, others represent fish vertebrae, while others imply jellyfish. If you visit the Bowers Museum in Orange County, you will see a convincing display of this. However, it does not explain ovoid or clover forms or the drastic range in the number of individual cogs. Another view is that cogged stones may represent notable stars in the night sky, but there is little to back this view at the moment (Koerper 2006).

    Recently, Paul Apodaca has raised the idea that they represent cactus slices. This is based upon ethnographic studies of the Seri Indians of northern Mexico. During fiestas and puberty ceremonies the Seri play a game with cactus slices called camoiilcoj. They utilize different sections of cactus from numerous cactus species which, when viewed as a whole, express almost the entire range of cogged stone forms. Interestingly, it has been noted by ethnographers that the Seri use stones to replace cactus slices when cacti are not available. It has also been noted that the Seri perforate cactus slices and gouge out sides which explains perforations in cogged stones and the fish vertebrae class. Apodaca postulates that the use of cogged stones may be the Cactus Stones, as Apodaca calls them, were a means for the culture to continue cactus symbolism in the absence of cactus. More interestingly, the Seri have been linked linguistically to the Hokan linguistic group which ties them to the Chumash of coastal southern California. Historically, the tribe's range extended to within some 40 miles of the Santa Ana River. Prehistorically, it is possible that people of the same linguistic group and similar culture inhabited what is now Luiseno and Gabrielino territory. It is this author's view that the sudden disappearance of cogged stones may be related to the migration of Uto-Aztecan peoples—like the Luiseno, Gabrielino, and Cahuilla—into formerly Hokan lands.

    The actual events that created the Cogged Stone culture, and what caused their abrupt end, what they symbolized, and who made them, will likely never be satisfactorily answered. However, it is possible to take the information at hand and interpret it with your best guess. In essence, they were a pillar of a long gone culture. Likely ceremonial and symbolic in nature, they held a strong significance to a people we will never know. Important enough to be created and replicated for over two millennia, we are still unable to definitely determine the purpose of these cogged stones.

    Special thanks to Eddie Anderson, Miriam Slater, and Paul Goldsmith.

    Devlin Gandy is currently working on a Degree in Anthropology and living in the Santa Monica Mountains north of Los Angeles, California.

    Duplicated from the “Resources” section of and reproduced with permission.
    I keep six honest serving-men (they taught me all I knew); Their names are What and Why and When and How and Where and Who.

  • #2

    The largest cache of cogged stones discovered so far was unearthed in late 2006 at the Cogged Stone Site in coastal Orange County, California. The cache, in combination with other smaller caches has led to the development of a new typology for these artefacts. You can download a copy of “Saved by the Well: The Keystone Cache at CA-OR A-83, the Cogged Stone Site” by Jeffrey S. Couch, Joanne S. Couch, and Nancy Anastasia Wiley here:
    I keep six honest serving-men (they taught me all I knew); Their names are What and Why and When and How and Where and Who.


    • #3

      An unusual example made from red ochre was found in Orange County, California and reported in the 1998 Pacific Coast Archaeological Society Quarterly 25(3):25-45 by Henry Koerper and Roger Mason. You can download a copy of “A Red Ochre Cogged Stone from Orange County” here:
      I keep six honest serving-men (they taught me all I knew); Their names are What and Why and When and How and Where and Who.


      • #4

        Mystery surrounds the purpose, value, and symbolism of the so-called “cogged stones” of Southern Galifornia (Ghace 1965; Eberhart 1961; Smith 1968). They are dispersed over a wide area of the historically recorded Uto-Aztecan language group of southern California. Some few are found within Ghumashan (Hokan) territory, and at least one was recovered within the Yuman (Hokan) language landscape.

        Paul Apodaga goes on to suggest that the term “cogged stone” should be replaced by the term “cactus stone” and that these artefacts may represent slices of columnar cactus. The Seri people of Northern Mexico and Southern California use such cactus slices in a game known as camoiilcoj, which is played at fiestas.

        You can download a copy of his paper “Cactus Stones: Symbolism And Representation In Southern California and Seri Indigenous Folk Art and Artifacts” from the Journal of California and Great Basin Anthropology Vol. 23, No. 2, pp. 215-228 (2001) 215 here:
        I keep six honest serving-men (they taught me all I knew); Their names are What and Why and When and How and Where and Who.