Archive for April, 2008

Basalt masonry

15 April 2008

basalt

I took a walk this morning among my local steep hills. Near the Rose Garden, I spotted a resident clearing his front yard, which was full of Oakland-quarried boulders. He had dug out all the old junipers and was making terraces with the rocks. I told him they’re special now that Oakland has no working quarries. He said he’s trying to get his neighbors to tear out their junipers too—all the houses have these rocks, probably dating from the twenties when they were built. Then I crossed the Chetwood bridge into Adams Point and inspected a bunch of yards of the same vintage, where the same landscaping rocks were common. My guess is that the Leona quarry was the source. I still know little about the Hiller Highlands quarry, but the rock there is different. There are piles of old quarry rock in the slopes below Merritt College that match some of the stones I saw.

But after crossing to the Auto Row neighborhood via the Perkins and Frisbie stairways, I passed this exceptional house along Richmond Boulevard. The stone fence is noteworthy with its jagged top. I shot this picture in 2006; right now it’s covered in vines. And the porch behind it is a splendid example of stonemasonry. It’s all made of basalt stones, and I’m guessing that the rock came from the Round Top quarry (or conceivably the Rockridge Shopping Center quarry). But some time I need to visit the History Room at the main library and find out just what the local quarries produced and when they were active.

Firm clay

13 April 2008

clay

On two occasions I’ve spotted construction sites on the fringes of Haddon Hill, once at the corner of MacArthur Boulevard and Wesley Avenue and once at the west end of Brookwood Road. I asked what the ground was, and both times the owners said the same thing: “firm clay.” There is no bedrock to speak of west of the Hayward fault, outside the Piedmont block and Toler Heights, up where 98th Avenue ends. It is safe to say that any Oakland neighborhood named “Heights” or “Highlands” has some bedrock under it, and some of the “-monts” do. But the rest of the hilly places that adjoin the flats are firm clay, with maybe a little sand and gravel. If the slope isn’t too steep, this soil is good for building.

All are part of a large alluvial fan dating from late Pleistocene times. It stretches from Pill Hill to Evergreen Cemetery, and its closest approach to the Bay is here at San Antonio Park, overlooking Coast Guard Island.

san antonio

Its sediments are said to contain “extinct late Pleistocene vertebrate fossils.” I haven’t read the literature, but that could mean anything from Ice Age mice to the mammoths, horses, camels, sloths and bison known from other Bay area sites, not to mention some extinct great cats. It’s worth keeping an eye on this stuff.

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


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