Archive for April, 2008

Geologic people

10 April 2008

A few months ago I attended a geology walk in the hills above Claremont Canyon, led by UC Berkeley’s Doris Sloan. Doris is not only a great teacher of geology, but the author of a great book, Geology of the San Francisco Bay Region by UC Press. It has enough content — maps, charts, text and John Karachewski’s superb photos — for several decades worth of day trips and outings and repeat visits. (Even so, the book has little about Oakland. Sibley Volcanic Reserve is in it, of course, but that’s mostly outside the city limits.) Hanging out with Doris, I felt like Watson next to Sherlock Holmes, but then look what a great career Watson had as Conan Doyle’s ghostwriter.

My point is, it takes more than websites, more than books, more than rambling in the hills on your own to learn geology. Tagging along with experts is a great help. If you get the chance, take a walk with one. Our area is blessed with good geologists at Cal and at Cal State East Bay, at Stanford and UCSF and many other institutions.

Sidestepping Piedmont

9 April 2008

glenwood glade

This morning I took a hike that circumambulated Piedmont without setting foot in it, while also incorporating pedestrian stairways and paths. There was something to see at every step; here are two highlights. The first is the charming hidden street of Glenwood Glade in the Fernwood district (what I would have called northern Montclair), where I snapped this verdant front yard with indigenous boulders. The whole street runs directly upon the Hayward fault. I would enjoy it now, because it isn’t likely to survive the next major rupture.

Then below is the Zion Lutheran Church on uppermost Park Boulevard, isolated on the very edge of Piedmont overlooking Dimond Canyon. Why would a church be dug into a bedrock hillside? The answer is, it wouldn’t; this is a former quarry. I stayed across the street, not wishing to touch Piedmont soil, but it looked like massive Franciscan sandstone, just as it’s mapped.

piedmont quarry

The roadway of Park Boulevard through Dimond Canyon is so massively reinforced that I suspect there was a railway there first. Does anyone know the history there?

Our lady

8 April 2008

our ladyOur Lady of Lourdes Church sits at the foot of Haddon Hill by Lake Merritt. Haddon Hill is said to be where the first Mass in the Bay area was celebrated, on 27 March 1772, and a nicer spot couldn’t be found. As I admire this building, what strikes me is the timeless vision that it memorializes. The sacred Virgin appeared in 1858 to a French girl in an underground spring, the grotto of Lourdes. Such a thing is in keeping with the most ancient chthonic traditions of Europe, traditions that may date back to the Neandertals.

At about the same time, in 1859, Darwin published On the Origin of Species, laying out a theory of life that did not need the divine. The notion of a godless cosmos was in the wind at that time. But we demand a personal link with the cosmos, and for many that link is Our Lady of the ground, overseer of our births and deaths.

My own upbringing disposes me to forge my own personal link to the universal cycle. My Lady is the Earth, who brings us forth and takes us back in a marvelous sustainable cycle. My views are closely aligned with how Walt Whitman responded to the same Earth in 1860:

Now I am terrified at the Earth! it is that calm and patient,
It grows such sweet things out of such corruptions,
It turns harmless and stainless on its axis, with such endless successions of diseased corpses,
It distils such exquisite winds out of such infused fetor,
It renews, with such unwitting looks, its prodigal, annual, sumptuous crops,
It gives such divine materials to men, and accepts such leavings from them at last.

This is an entry in The Accretionary Wedge #8, Earth Day

Lowland slides

7 April 2008

As Darby commented on an earlier post, you don’t need to be in the hills to find hazards. A good fraction of the residential landslides in Oakland get mentioned in the Tribune, and they happen downslope, too, mainly along the creeks. Last week my buddy Jef visited a notorious example along Wallace Street, downvalley from Highland Hospital. The one above, on McKillop Street in the Fruitvale neighborhood, made the news throughout 2006, and I prepared a rudimentary case study of it for my About.com site.

The clues are plain, both on the map and on the ground. Look below: Just a few steps from that pitiful collapsed house is this view toward the hills. It’s pretty; it’s worth a little extra on a home’s selling price. But why is there a big empty space in the middle of one of Oakland’s older neighborhoods? A fire might clear a lot of land, but people would rebuild. Why does McKillop Street have two parts, one here and a stub at the far end of the park? Why isn’t there a nice bluff along Sausal Creek like there is elsewhere?

Claremont Chert, close up

6 April 2008

claremont chert
The Claremont Chert is a distinct rock unit that I described a bit in an earlier post. This is my official hand specimen of it. You’ll find it halfway up Claremont Canyon and along both Skyline and Grizzly Peak boulevards until they intersect near Round Top, where it leaves Oakland territory. Canyon sits on it, and it underlies the east side of Upper San Leandro Reservoir farther south. To the north it pinches out just north of Claremont Canyon, so it really is an Oakland stone.

It’s got some clay content in it, making it look chalky rather than flinty. I like its fine layering. Until just a couple years ago, the spectacular exposures along Skyline approaching Grizzly Peak Boulevard were in deep shade and shrouded in brush. Since the upper catchment of Temescal Creek was opened up, removing dense stands of eucalyptus (and using poison to keep them removed, thank goodness), the chert has become dazzlingly exposed with its contortions laid out in plain sight.

Oakland’s boulder lovers

1 April 2008

5855margarido.jpg

Berkeley is more famous for its elegant century-old hill neighborhoods that respected the local rocks, such as the Thousand Oaks district. But Oakland shared in that era of rock adoration, and the same developers did their work in both cities. This house on Margarido Drive is in the block of Franciscan mélange that underlies the town of Piedmont and surroundings, and the owners have draped this imposing knocker with vines. Not having my hammer with me, I refrained from giving it a field examination. Other Margarido homes display the local bedrock to advantage too.


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