ASBC Victoria September 18th 2012: Public talk on bedrock stone bowls by Beth Weathers

Stone Bowls in bedrock at Willows Beach, Victoria

Stone Bowls in bedrock at Willows Beach, Victoria. Photo courtesy of Beth Weathers.

Investigation into Intertidal Bedrock Bowls at Willows Beach, Victoria.


Tuesday Sept 18, 2012, 7:30 pm Pacific Forestry Centre,
506 West Burnside Road. map

Free and Open to the Public

Overview (via ASBC): In 2009, Beth Weathers was informed by a local resident that there were some “Indian Bowls” in a bedrock outcrop at Willows Beach in the Oak Bay area of Victoria. Upon investigation, Beth identified and recorded 27 bowls that have been ground into one granite outcrop near the mouth of Bowker Creek. These bowls, and others like them, will eventually became the topic of her MA thesis. Beth will present information and results to date from her studies into these fascinating ancient features.

Bio: Beth Weathers has worked as a professional archaeologist for over a decade, first in Cultural Resource Management consulting, then at the British Columbia Archaeology Branch, where she is still employed. She was also instructor and TA for two semesters at UVic during her spare time.

Note: At the completion of Beth’s presentation a brief period will be devoted to the Annual General Meeting business.

For information, e-mail

PS: While we’re talking public talks, where is the Archaeology Forum going to be this year?

17 responses to “ASBC Victoria September 18th 2012: Public talk on bedrock stone bowls by Beth Weathers

  1. Looks very interesting Beth!

    And Archaeology Forum info is in Cranbrook, Oct. 26-28th.


  2. glad you posted this or else i would have missed it…… cant wait to hear beth speak about this


  3. Beth: Wish I could be there, but term starts that day (and in Olympia, WA). Being in OAK Bay any thoughts about use to process/grind acorns too? May be too close to all that salt water though. Thanks and look forward to thesis, Dale


  4. Beth Hill did a presentation on bedrock bowls and mortars in the Gulf Islands area, I think at a rock art conference (or possibly the NW Anthro conference?) in the 1980s. I don’t know if there was a paper published, but I do remember the presentation and think it might be of interest to Ms. Weathers. There are bedrock bowls on Saltspring Is. (near where Beth Hill used to live), in Sansum Narrows on the Saltspring Is. side, and at Degnen Bay, but I believe Beth Hill mentioned quite a few more.


  5. I found one in Port Alberni, which Beth W. knows about. I think that is the furthest one from the Salish Sea that I know of (and of course, there are varying lines of evidence showing an early Salish presence in the Port Alberni area).

    Dale, I don’t believe there is any evidence at all either in ethnographic accounts or archaeological, of acorn processing here. Which is kind of surprising seeing that it was a staple for the large populations of California and southern Oregon. If I’m wrong, it won’t take long for me to be corrected I suspect!


  6. Hi Morley, I am sure Dale will be along with info, but in meantime, check out: “Balanophagy in the Pacific Northwest: The Acorn-Leaching Pits at the Sunken Village Wetsite and Comparative Ethnographic Acorn Use.” by Bethany Mathews
    . Journal of NW Anthropology 2009. Volume 43(2):125–140.

    Reprinted in a great collected JNWA volume which is open access and available online here:

    Click to access Trad%20Resources%20Vol%201.pdf

    Acorn shell fragments have been excavated in large quantities at Qwu?gwəs (45-TN-240), a Squaxin shellfish processing site near Olympia, WA, where acorns greatly outnumber other midden plant food remnants (personal observation 2008). It is unlikely that these are the remnants of rare instances of use which by chance were preserved in a waterlogged environment. The presence of this resource at these sites suggests that acorns were more ubiquitous in middens throughout the Northwest.

    The scale of the Columbia River operations is effectively given here in this snippet from Heather Pringle:

    And another source of carbohydrates has turned up at the Sunken Village site along the Lower Columbia River. There, a team led by archaeologist Dale Croes of south Puget Sound Community College in Olympia, Washington, and Akira Matsui of the National Cultural Properties Research institute in japan recently mapped 114 shallow pits littered with the remains of Oregon white oak acorns. The team’s studies revealed that aquifers at the site regularly flush water through the pits. By simply storing acorns there over winter, ancient people leached the bitter tannins from the nuts, making them more edible. Based on the pit sizes, Croes and colleague Bethany mathews estimate that people processed as many as 2.5 million acorns at the site each year. “You just don’t think of acorns as being a way of making a living here,” says Croes. “It’s poorly understood that plant foods are a major part of the economies.”


  7. Morley: Beth is brilliant in this analysis and research. Oak were common well up into southern BC, so I have little doubt that acorns were used, especially with the rarity of carbohydrate foods along the NW. Take a look at Beth’s work and think about your region from 8000–4000 BP when environments were even dryer and warmer, with oak grooves similar in size to Oregon and California. These thoughts were explored by Donald Mitchell early, and now we are beginning to see the wet site archaeological evidence. 2.5 sweetened acorns a year makes a lot of soup! Dale


  8. I meant to say 2.5 MILLION acorns a year–so where are the oak trees today–I visited the farmer who owns the Sunken Village site and asked him that question–he pointed to his floors, and said he milled the wood himself! DC


  9. I still don’t see how solid (non porous – not suitable for leaching?) bedrock bowls in the intertidal zone help with acorn processing, which I don’t deny is real and something we need to get on top of up here as well. If they date to 8,000 or something then yeah, they wouldn’t have been intertidal of course and would be easier to think of as essentially metates (though I still tend to doubt that).

    I wonder what a predictive model for acorn-leaching sites would look like? What specific local environmental variables are a pre-requisite?


  10. Interesting, had not read about acorn leaching pits in the NW before, but makes sense. Here’s a pitted boulder used by the Maidu in northern California I came upon a few years ago.


    • Thanks Greg — that’s a very, very striking picture. I guess there is a continuum with cupules at one end and massive bedrock bowls at the other, and it’ll be interesting to see us get a handle on interpreting these up here on the coast where relatively little work has been done anywhere on that spectrum.

      My own opinion — based on not a lot — is that the Willows beach bowls are not that suited for leaching — or, that they are overkill at the best for the task, and perhaps ineffective too. I mean, the biggest are about the size of a salad bowl, and that would be about half an hour of picking up acorns to pick, and does one even want a bedrock bowl for leaching versus the documented basketry-permeable ones noted up-thread. To me, acorn leaching is a huge topic we should address, but I don’t see a necessary connection to these bedrock bowls. I’m willing to have it explained to me by anyone willing though, how a bedrock bowl is better for leaching acorns than a basket in the water…..


  11. I sadly haven’t made much time to study the use of acorns in BC yet, but I would not be discouraged by a lack of ethnographic accounts. Unfortunately, even where we have archaeological evidence for acorn use in Washington and Oregon, the ethnographic evidence is slim. And as we’ve recently seen in northern Oregon and southern Washington, this lack of archaeological evidence (to date) may not represent past behaviors.

    If we assume acorns were being used in southern BC, it is most likely they were being roasted or passively leached, based on cultural similarities with the immediate south. So a bedrock mortar dedicated to acorn flour processing and leaching seems unlikely.

    Since acorns are dropping right now I’ve been working on some experiments/recipes, and tried a slurry leaching method in a mortar and pestle. Processing fresh acorns by pounding and actively leaching (it would be pretty handy to have water within reach for this) isn’t impossible, but from my trial would probably be quite a bit of work. If you couldn’t store them to leach in a water body or aquifer, and you couldn’t roast them (or didn’t like the change in flavor), I suppose this would be the next best thing. Based on my fairly limited experiments, I’d say if you were looking to pound and then actively leach acorns, a large stone bowl on the water would be a good place to do that.

    Passive leaching by placing acorns in a bowl does make some sense (another method I’ve tried and have got going on in my kitchen right now), but would require time. And in that case, you might as well find some other container to soak them in.

    The predictive model question is a great one. I wish I had an answer. So far it seems the most common element, archaeologically speaking, is aquifers.


  12. Is it possible that these bowls were baited with small fish or other foodstuffs to attract mink, weasels, marten and the like and they were snared or otherwise captured there?


  13. Bethany – belated thanks for your comments on this post – very enlightening.
    Allan – that’d be worth looking into. Being right in front of a busy village might argue against that, but at the same time, intertidal traps would be easy to tend with people nearby. It does seem to be a lot of work to put the trap into solid rock, and then have several dozen of them in such close proximity.


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