The Science of Sustainability

Producer's Notes: Ice Age Bay Area

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At Sonoma County State Beach, just south of the mouth of the Russian River, stand two seastack rock pillars surrounded by large boulders. The prominent blue schist rocks form something like an amphitheater above the coastal cliffs.

There is something about these rocks that draws you in. Maybe it's the way they jut out of the ground? Or perhaps it's the "Stonehenge" way they form an enclosed circle? Or maybe it's just a nice place to get out of the wind? Whatever it is, they seem to pull you towards them. And once you are there, they almost call out to be touched. The rocks, long known as the "Sunset Boulders," have attracted rock climbers for years. I've climbed these rocks before. But like so many other people, I had no idea I was touching history.

During the Pleistocene, 10 to 20,000 years ago, this place was very different than it is today, inhabited by massive mega-fauna; bigger elephants, lions, bears and wolves, than we see today. While those big animals went extinct thousands of years ago, they left their mark on this place.

Looking around these rocks it is easy for me to imagine the herds of Columbian Mammoths lumbering from the nearby wallow to rub against the boulders. I can picture huge herds of camel and horse grazing nearby. Yes, those animals evolved here in North America and then crossed into Asia where they thrived and survived. Weaving my way between the boulders, I can imagine how the predators could have used these rocks as an ambush site. I envision a huge saber-tooth cat slinking between the craggy rocks, looking to pounce on an unwary bison. I can see the prides of American Lion, similar but much larger than African Lions, basking on the tabletop boulders after a big kill. I can also picture the ultimate predator making their campsite here when that first hunting party foraged deeper inland. Yes, humans were here too. And I'm sure the same pull these rocks have today existed back then.

This seems like a sacred place to me. Sacred to history. So when you visit these rocks think about those who came before you. Think about the mammoth and the bison and the camel and the horse. Think about the lions, tigers, bears and wolves. And think about those first people. Tread lightly and respect this wonderful place. With care, these rocks will be here long after we all become part of history.

Special thanks to the San Diego Natural History Museum for contributing artwork and HD video to our story. Also, to see more artistic representations of Pleistocene mega fauna, by the artists who contributed to our segment, see:

Laura Cunningham's artwork

Artwork of Joseph Venus

William Stout's wonderful murals


Watch the Ice Age Bay Area television story online.

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Category: Biology, Geology, Television

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Chris Bauer

About the Author ()

Chris Bauer is a Media Producer for QUEST. Chris has nearly 20 years experience working in broadcast television; producing sports, history, technology, science, environment and adventure related programming. He is a two-time winner of the international Society of Environmental Journalists Award for Outstanding Television Story and has received multiple Northern California Emmy Awards. Some of his Quest stories have been featured in the San Francisco Ocean Film Festival, Jackson Hole Wildlife Film Festival, United Nations Association Film Festival, the BLUE Ocean Film Festival and the Environmental Film Festival in Washington DC. A 5th generation Bay Area resident and a graduate of St. Mary's College of California, his hobbies include canoeing, snowboarding, wood-working and trying to play the ukulele. He and his family live in San Francisco.
  • Dan Granett

    Mr. Parkman's discovery of the animal polished rocks is quite plausible except for his naive conclusion that the height of the tallest polished rock indicates the height of the animal that rubbed it.
    Ground levels around the rocks can vary wildly even from year to year after mudslides, heavy rains and earthquakes.
    Still, great show.

  • E. Breck Parkman

    The results of subsurface observation and geomorphological analysis suggests that the current surface around the polished rocks approximates that of the terminal Pleistocene.

  • Erik

    I don't think it's at all naive. After all, how will we learn without someone willing to make a bold statement and then listen to its critiques? That said, I recognize all of those polish marks as key handholds and footholds for the local rock climbing community. That area is famous for "bouldering" where you climb 15 feet or so with no ropes and then fall onto pads. How did you exclude the possibility that it was just climber polish?

  • E. Breck Parkman

    At Sunset Rocks, there are vertical rock faces where a continuous and uniform polish extends for distances greater than 12-15 feet horizontal and 6-8 feet vertical. Climbers must certainly account for some polish on rocks, but they can't create polish like that. That said, the polished rock "knobs" used as hand and foot holds by boulderers at Sunset are likely being further polished by the climbers. At Sunset, though, the raised knobs account for a small fraction of the actual polished surfaces. I spent the first few years of my research observing and interviewing climbers at Sunset in order to delineate any effects they were having on the rocks. I have a pretty good idea of how and where climbers utilize the rock. Most of the polished areas are also areas that see regular climbing, but the climbers do not come in actual contact with the vast majority of the polished surfaces, with the exception of the raised knobs used as holds. I should also note that I have found several other similarly polished rocks within a few miles of Sunset Rocks that are absolutely not climbed or bouldered. I spent three years conducting a large-scale archaeological dig at one of these other nearby sites, and found polished rock faces buried beneath the current land surface in sediments radiocarbon dated to the late Pleistocene (20,000calYRBP). All of these polished rocks, Sunset included, are identical to well-known buffalo rubbing rocks on the Northern (Canadian) Plains (which I've personally studied) as well as contemporary elephant rubbing rocks in Africa (which I haven't yet visited). That obviously doesn't prove that Sunset Rocks and the other nearby occurrences were polished by Ice Age mammoth and bison, but these megamammals do appear to be the most liklely suspects based on all the research my team and I have conducted to date. But I'd be perfectly delighted if someone else comes up with some other explanation that proves correct. In the end, Science isn't about being proven right or wrong, but about determining the truth. We may never truly know just who or what created the polish at Sunset Rocks, but regardless, the quest to determine the truth is an amazing and exciting journey that we are all part of.

  • http://www.bodegabaylife.com Kathlene

    Thank you for this fascinating report. I live in Bodega Bay and posted your link in my blog BodegaBayLife.com. Please keep up the great work, we need more documentation of our natural history like this.

  • Chris Bauer

    The excavation of a fourth bore of the Caldecott Tunnel between Orinda and Oakland is tapping into a time capsule. Paleontologists are sifting through the rubble in search of fossils expected to give clues to old life-forms and climate change in the Bay Area. To learn more about the process and what they are discovering, check out:

    http://www.insidebayarea.com/oaklandtribune/localnews/ci_15533976?source=rss