Archaeologists, This Is Your Chance to Shine!

A Bear submitted a bit o’ a puzzle. Good thing, too, as I am deep in frantic research and prep for a trip to Mount St. Helens this weekend, so I haven’t time for anything gorgeously detailed. Especially not since WordPress ate my gorgeously-detailed prior post. Grr.

I’ll just quote from his emails:

Artifact or artefact? This rock came from the beach nearby, is it a product of natural forces or culture? This rock originated from the Karmutzen formation on Vancouver Island and has been entrained in glacial drift as well as marine beach activity by my guess.

Given the odd shape has it been culturally altered?

It would be interesting to see what your readers can make of this.

There is a midden nearby that is eroding onto the beach where I have found some nice artifacts, so it would not be out of place.

If there is interest in its composition, it is dense, specific gravity of almost 2.5, fairly hard and the black crystals appear to be magnetite as the rock has a fairly strong attraction to my neo-magnet.

So there’s some lovely detail, and we have photos, complete with scale:

Rock or artifact I
Rock or artifact II
Rock or artifact III

If this had been found in Arizona, I’d be tempted to call it a mano, which is the bit Native Americans there rubbed against metates to grind corn. I don’t know if our local tribes used anything like that. And I have no idea how to tell the difference between a wave-smoothed rock shaped like a lozenge and a human-smoothed rock shaped like a lozenge.

What say you all?

Also, consider this practice. Trebuchet sent me a riddle I’ll be springing on you soon, and it is brutal. This is your opportunity to sharpen your brains in anticipation. Use it wisely.

Archaeologists, This Is Your Chance to Shine!
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14 thoughts on “Archaeologists, This Is Your Chance to Shine!

  1. 1

    Disclaimer – I’m a uk medieval archaeologist, although have done some prehistoric stuff over here, but have never worked on the sort of site you’re talking about.

    Looking at the photos, I’m not seeing anything that obviously says ‘worked by humans’, or even ‘natural lump used by humans’. Are there any photos of the ends, which might show some extra wear if it was used for pounding/rubbing? The key piece of information we’re missing though is whether that rock is like most of the other rocks on that beach, in which case it’s probably natural (although may have been picked up and used by someone who thought it looked just right for a task) or whether it stands out as unusual for the area, and therefore brought by people. That’s not such a good distinguisher for a beac site as for an inland one though, because ocean distribution is always more surprisingly effective than we tend to expect.

  2. 2

    The rock is a granite, by the look of its grain size/distribution/color. The density offered by “A Bear” is consistent with granite – and relative to a lot of rocks, it’s actually not all that dense.

    Seems to me that context is everything when it comes to archaeology – where this thing was found is critical for reasons of distinguishing it from local geology and proximity to dwellings and metates and such. As presented, it’s just an isolated cobble with a a length that’s about twice its width.

  3. 3

    I’ll defer on the artifactness of the stone and stick with what I know.

    A magnet will be attracted to many different minerals other than magnetite. Such minerals are said to be “magnetically susceptible”. Magnetite has a strong proclivity to oxidize fairly rapidly as well. Therefore, I would think that the dark mineral grains are not magnetite.

    I will add that it seems quite a bit smaller than manos I have seen.

  4. 5

    You find that on a beach with lots of other stones and you can easily say “natural”. If you found it next to a metate in a village midden you would conclude “artifact”. Context is very important.

  5. rq

    What if it’s a rounded, smoothed stone that happened to be useful? What I mean is – the shaping might not be cultural, but due to its shaping, it may have been used culturally… In that case, what is it, a rock or an artifact? Context and all that.
    Anyway, I’m also going with granite, but I’m basing that purely on appearance.
    Perfect for cobblestones, though.

  6. 7

    Long term wear on a mano will add polish to the high spots on the stone. Hold it to the light at an angle and look for the polish–which should only be on the high spots.

  7. 8

    To answer one of your questions – some tribes in PNW did use mortar and pestles. My OR coast tribe used to use ’em for grinding acorns (which we got in trade from inland valley people) and manzanita seeds.

  8. 10

    The shape looks slightly unusual, in that the ends seem somewhat square, with slight rounding of the corners/edges. I feel that most cobbles that have been kicking around in nature for a while tend have more of a well-rounded elliptical sort of shape (not that there aren’t numerous exceptions)

    Not so much that I think I would notice it would I walk across it on a beach.

    Possibly a cobble/brick that’s suffered recent weathering? I’ve seen numerous pavings and small structures made of brick sized/shaped blocks of granite. I’m thinking it’s pretty likely something like that got dumped in as erosion control, or to build a jetty or something, and the individual brick got knocked/worn out, tumbled around a bit to smooth the corners off without completely rounding it…


  9. 11


    I’m doubtful it’s a last. I’m not well-schooled on this sort of thing, but I’ve run across a few descriptions of moccasin-making on various survival and primitive living books, and most of them were along the lines of: “trace around your foot. draw another outline about an inch bigger. cut it out, and punch a bunch of holes in it and lace it” (a bit more specific/involved, but a still a pretty basic process). So I’m not sure why one would need a last for a soft shoe like a moccasin.

  10. 12

    Yeah, that seems to be the general consensus. It came, as far as I know, from Montana. It does seem kind of doubtful that the Plains Indians would want to be carrying rocks around on their travels, just to make one size of shoe!

  11. 13

    In the local museum there is a boulder with a bowl fashioned in it that was taken from very near where I found this rock so the location is a good one.
    I plan to go back to the beach to get a naturally weathered rock of the same type to compare wear and see if it has a raised polish or other signs not evident in the naturals.

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