Rocks in the gutter

Down in the Chinatown and Produce District area, we have some special rock-lined gutters, ranging from fine . . .

to crude . . .

to funky.

They’re the nearest thing Oakland has to cobblestone streets, and they serve the same purpose: heavy duty traffic.

The variety of these gutters suggests that they were emplaced over a long period, under various city contracts. Given that, it’s probable that the stones come from several different sources. But nearly all of them are basalt, the fine-grained, gray to black lava erupted from volcanoes up and down the western states.

These days basalt is a fancy stone, as seen in finer landscapings like the courtyard of Berkeley’s new School of Public Health building. These are natural hexagonal cooling columns of basalt, like those up at Devils Postpile in the high Sierra, cut and polished for elegant seating.

But our gutters are lined with prosaic basalt. And I think some of it came from our own hills. The Sibley Volcanic Regional Preserve includes the grounds of several former quarries that produced basalt rock. In 1906, State Mining Bureau Bulletin 38, The Structural and Industrial Minerals of California, reported on the first of these, the Ransome Quarry: “This quarry is on the Old Fish Ranch road, about 5½ miles from the Oakland City Hall. It was opened in April, 1904. A tramway 600 feet long carries rock from the quarry face to the crusher at side of road. The rock is a fine-grained basalt, and is used for macadam and concrete. Some gutter rocks are sorted out. The rock is hauled to Oakland and Berkeley by wagon.”

Sibley’s lava flows aren’t the enormous, massive ones of Oregon and Washington’s Columbia River Basalt, a genuine Large Igneous Province widely attributed to the hotspot that now underlies the Yellowstone region. The Sibley volcano is a dinky thing with a lot of different deposits ranging from ash beds to proper basalt.

I like to think that a couple workers up there kept their eye on the rock and picked out good bits for this premium trade. I imagine that those are the rough gutter blocks. The later street contracts probably used more economical, higher quality material from farther away, like the North Bay counties or even Black Butte up near Orland.

Nowadays, for better or worse, we keep it simple and use concrete or asphalt, even though the work needs more repairs.

5 Responses to “Rocks in the gutter”

  1. JB Says:

    Thank you for another great post!
    I have a pretty silly question but here goes.
    The bulletin in 1906 mentions “Old Fish Ranch Road.” Is the “old” referring to the road or the ranch? Either way, it makes me smile. The idea of anything already being called “old” in 1906 is a nice perspective shift.

  2. P. Michael Hutchins Says:

    columnar basalt seating

  3. Andrew Alden Says:

    Scott, thanks so much for that tip!

  4. Scott Bowman Says:

    A fascinating account of the quarrying, cutting and use of these stones is: “A History of Paving Blocks Along San Francisco’s South Beach Waterfront”, Olmsted, Nancy, 1991. You can find it in libraries or (maybe) online for download. It somewhat debunks the ships ballast idea. I like these stones, but have visited a couple of the quarries in the North Bay and it is clear that they destroyed what must have been spectacular columnar basalt outcrops along the hilltops.

  5. Erich Hayner Says:

    I had always been told, from various sources, that basalt pavers were repurposed ballast from ships transporting goods up and down the West Coast. Not being my specialty, I have no idea why ballast would be discharged from a ship in the first place.

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