Oakland is in an unusual situation. Right now, nobody is exploring Oakland geology, yet the city has a great variety of features worth attention and even celebration. I’d like to see that change, which is one reason I began this blog just over a year ago. Right now, Oaklanders are spreading their attention on fresh culture, the creeks, the government, business, the lake and their houses and families and neighborhoods. People are outdoors—I see them almost everywhere I go—but nearly all of them are either construction crews, joggers or bicyclists. They aren’t there just to BE there. (Maybe I’m not either, strictly speaking, but let’s let that go.) Even if they set out to enjoy some of Oakland’s geology, there are no trails and almost no interpretive exhibits. And even if there were trails, I’m not sure I would favor that because development brings degradation. Let me give an example or two.
Mount Tamalpais, in Marin County, gave rise to mountain biking, starting in the seventies with a close fraternity of obsessive amateurs. Today the sport is an industry that benefits many thousands of people, some of whom—just a relative few—are poor citizens that blaze unsupervised trails and abuse existing ones where they are prohibited. The rocks of north Berkeley, most notably Indian Rock, spawned a lively school of rock climbing starting with the David Brower crowd in the 1930s, and today Berkeley’s public crags are so overrun with exercisers of all ages that visiting for any other purpose is difficult.
All this is just to say that if the geologizers of Oakland are ever to increase in number and sophistication, we have to build in righteous field manners, responsible enthusiasm, at the foundation. For the Oakland amateur, the city’s landscape is as good as a wilderness, and my own practice is evolving toward the wilderness ethic of the Sierra Club: take only pictures, leave only footprints. For some time to come, Oakland geologizing will be, not exactly underground, but unsupervised. And because “to live outside the law you must be honest,” I want to set a personal example of self-restraint.
And so one of my watchwords as I traipse about our streets and slopes is “leave the stone alone.” We aren’t real geologists, with a job to do that requires us to sample and hammer and drill the outcrops. We’re just out there to enjoy and learn, and I believe we should treat Oakland, for the most part, like a park. Everything I show you here in this blog is something I’ve left behind unblemished, so that you can enjoy it just as much.
Oakland Geology 
11 March 2020 at 10:10 am
My grandfather used to climb with Brower at Indian Rock back in the 1930’s. They went backpacking in the high country of Yosemite and met Ansel Adams on one trip. They lost touch after the war.
13 October 2008 at 11:26 am
Thanks for clarifying that. BTW, although my ability to distinguish rocks is no more refined than distinguishing sandstone from granite, I enjoy what you write and I have been learning from your posts.
10 October 2008 at 1:27 pm
Yes there is. I think that bedrock is beautiful, and that if you want to study its minerals you either find a loose piece and break that open, or maybe you look for an outcrop under a bush and hammer on a corner of it that no one will see. That way, the bedrock is still beautiful and the scene looks untouched.
I’ve been on field trips with people who just haul out their hammers and bash away for no good reason. Sure, it was a roadcut, or a rock that wasn’t special, or behind a fence or whatever, but I think it’s important not to let your curiosity become self-righteous. I was on another field trip to a locality whose owner said no hammers, and seeing all that unmarked, stream-polished rock was like being in a temple.
I do feel bad in retrospect that I left the pieces of the concretion by the road; I should have tossed them downslope. But there are more concretions to be eroded from the roadside, and one was enough for me. And I collected the sandstone from a landslide scar that’s full of crumbled concrete foundations and loose boulders, a place where a few more broken pieces make no difference.
10 October 2008 at 12:58 pm
I hope you don’t take this as criticism because I’m not sure I understand: in your previous post, you wrote: “But I kept looking and eventually spotted a dark pod of rock—a concretion. I banged it open and this is what I saw.”
That seems like it’s in opposition to the principle stated in this post.
Or is there a difference between “big” stones and smaller, plentiful ones?