Archive for the ‘Other topics’ Category

In search of lime

25 May 2020

I like to brag that Oakland contains more rock types within its boundaries than any other city in America. But alas, it’s missing one of America’s most widespread rock types: limestone. Yes, there are pods of dolomite limestone in the Claremont Shale, but that’s a far cry from what Oakland’s first outside settlers hankered for, which was real calcite limestone.

Limestone is essential for civilization because it’s the default industrial source of lime (calcium oxide or hydroxide), without which you can’t manufacture any kind of decent mortar, or plaster, or cement. Lime has been made for thousands of years by simply roasting limestone, which consists of the mineral calcite (calcium carbonate). This was traditionally done in a lime kiln, a stone furnace that was loaded with rock and firewood.

The Bay area does have bodies of limestone, and these were staked out early. But the nearby firewood supplies (i.e. forests) were soon depleted, and the industry was fitful and limited until reliable supplies of coal and, still later, oil became available.

One alternative to limestone in Oakland was oyster shells, which we once had in abundance. Unfortunately, many of the old Native shellmounds had oyster shells in abundance too, and this led to the end of them.

A few years ago I had the chance to visit the remains of an old-fashioned lime kiln in the Santa Cruz Mountains.

Another old site was on the coast near Rockaway Beach, south of Pacifica. I wrote a piece about it for KQED a while back that explains where most of our local limestone comes from, tectonically speaking.

This kind of industry lasted only a few decades. Around the turn of the last century, big manufacturers started to mine massive bodies of limestone. One was on the Santa Cruz County coast at Davenport; it supported a company town out there for a whole century. Another was in the South Bay near Cupertino, based in a quarry on Permanente Creek. One of Henry J. Kaiser’s early companies operated it, and when Kaiser eventually became head of an industrial giant, during World War II he took the name Permanente for the name of his innovative company health-care plan. The quarry is still digging, almost 80 years later.


By Steve Jurvetson from Menlo Park, USA – Flickr.com – image description page, CC BY 2.0, from Wikipedia commons

Another big limestone quarry was in American Canyon, in Napa County. But the one that fascinates me most is the former Cowell lime quarry, which sits between Walnut Creek and Concord, on Lime Ridge. For about 40 years, starting in 1908, this quarry exploited a thick deposit of travertine — hot-spring limestone. It supported a company town too. Now some of the workings are in Lime Ridge Open Space, where you can scrutinize these unusual deposits. They aren’t like anything else around.

This post was inspired by my maniac brother Steve, who explores the woods around his Lyme, New Hampshire home to locate old cellar holes. Now he’s branched into old lime kilns.

In other news, I’m happy to report that the latest Covid-19 guidelines now allow the use of public transit for outdoor recreation. This means that all of my geology walks and rambles can be undertaken again, and I’m looking forward to getting out there, taking due care of course.

Geologists at Mountain View Cemetery

16 March 2020

Longtime readers will recall my post about Joseph Le Conte’s gravestone, which begins, “Joseph Le Conte (1823–1901) is probably the most eminent geologist in Mountain View Cemetery.” Last week I looked into that statement in more detail. Having made a thorough study — well, fairly thorough — actually pretty cursory, given the difficulties, I can say that Prof. Le Conte is probably not the most eminent geologist buried here. It’s arguable.

Here are all the other geologists I’ve been able to find, in the order of their deaths.

Ezra Slocum Carr (1819-1894) lies in plot 4, in an unmarked grave next to his wife Jeanne Smith Carr (1825-1903).

Ezra is significant in American geology for being part of the 1857 geological survey of Wisconsin, along with James Hall and Josiah Whitney. Ezra was a professor of natural history at the University of Wisconsin when Jeanne met a remarkable young man named John Muir. Together, the Carrs — no other word for it — cultivated him and maintained with him an intimate lifelong connection. Ezra gave Muir his first instruction in geology, something the Scottish-born farmboy must have soaked up like a sponge. When Ezra accepted an appointment to the new University of California in 1869, he became its first professor of agriculture. Muir had already come to California and been smitten with the Yosemite country. Jeanne arranged for Muir to meet Louisa Strenzel, daughter of a wealthy Martinez doctor and orchardist, who became Muir’s wife in 1880. Ezra later became the state Superintendent of Public Instruction.

James Graham Cooper (1830-1902) lies in plot 31, lot 15 right across from the prominent knocker. I haven’t found his stone yet, if there is one.

Cooper was a restless guy, trained as a doctor as so many early American naturalists were. His interests included botany, zoology and fossils, and he made many contributions to paleontology. He served in several Western exploring expeditions, most notably Josiah Whitney’s geological survey of California. He lost out to Joseph Le Conte as first professor of natural history at UC Berkeley, but still crammed a lot of accomplishment into his lifespan.

The remains of John C. Merriam (1869-1945) are in the columbarium, which is hard to navigate so I haven’t visited his niche yet. Instead here’s a fine, unengraved boulder of Franciscan chert in the middle of a plot.

If you’ve heard of California’s tar pits — the major ones in Rancho La Brea in Los Angeles and near McKittrick in the San Joaquin Valley — Merriam was the guy who led the first scientific excavations there on behalf of UC Berkeley. He described Smilodon californicus, the sabertooth cat, our official state fossil. He also co-founded the Save the Redwoods League, ran the Carnegie Institution and was president of the Geological Society of America for a term. The UC Museum of Paleontology has a page about him, as does Wikipedia.

Andrew C. Lawson (1861-1952) was buried at Mountain View but later removed to Toronto, presumably in a family plot up there but that’s where the trail ends. Here’s my favorite outcrop of Franciscan chert at the cemetery — Lawson gave the Franciscan complex its name.

Lawson, another Scottish immigrant, was very influential through his long tenure at UC Berkeley. He was the first decent mapper of Bay area rocks and a demanding instructor, emphasizing rigorous fieldwork. Many of the rock units around here were named by him. And of course he did heroic service after the 1906 earthquake, heading the Carnegie Commission that thoroughly studied the event in the aftermath. His two-volume report, published in 1908, is still known among seismologists as “the Lawson report.” He recognized and named the San Andreas Fault — wags suggest that he’d indirectly named it for himself. The mineral lawsonite is named for him.

But for my money, this guy buried in plot 6 is Mountain View’s leading geologist.

Nicholas Taliaferro (1889-1961), of the old Kentucky Taliaferros, pronounced his name “TALLifer” but his colleagues and students knew him as “Tucky,” presumably because of his accent. At UC Berkeley he succeeded Lawson in teaching field geology, up in these hills. In a Bay Nature piece in 2010, Erik Vance described Taliaferro’s teaching style, a story I used to hear too: “He would walk into the hills with his students, lean back on the head of his axe, stare at a rock, and light a cigarette. The confused students would look around, try to figure out what he was staring at, and start taking measurements. After a bit, Tucky would stand, wander to another rock, and have another smoke. If you missed it, you missed it.”

He ran the department’s Geology Summer Camps for 33 years, training more than a thousand future geologists to make sense of the land around them. And when he wasn’t doing that he patrolled the Coast Range and Sierra foothills, covering some 50,000 miles on foot and mapping 26 whole quadrangles, a land area probably exceeded only by the late Tom Dibblee. Every paper on Coast Range geology of any depth will cite Taliaferro’s work, even today. UC Berkeley has memorialized him on this page.

I would love to learn of other geologists buried at Mountain View. Or, for that matter, at any other Oakland cemeterySt. Mary, Home of Eternity, Home of Peace or Evergreen.

There is one more prominent California geoscientist I found: Eugene Hilgard (1833-1916), UC Berkeley’s first mineralogy professor, but far better known as a pioneer soil scientist. He’s in St. Mary, in the Dormitory B section.

Geology of Alameda

20 January 2020

Although these two distinctive cities are right next to each other and were settled at the same time, Alameda is a very different place from Oakland. One way to put it is that when you’re in Oakland, you see Oakland all around you. In Alameda, you see everything but Alameda around you.

And I like both of those things just fine. But in this post I’ll attempt to show the subtle ways Alameda reveals itself.

First a little history. The earliest map showing Alameda in any detail was Captain Beechey’s map of the San Francisco Bay, first published in 1833. Mainly a sailor-centric chart, it focused on the seaward edges of things. It shows Alameda as the peninsula it was until the 1890s, when the tidal canal was completed across its east end making it an island.

Two details are interesting. First, the map shows the seaward edge of the peninsula as an embankment rather than the typical marsh found around most of the Bay. A sandy bluff overlooked the beach and mudflats here. Second, the map used the same tree symbols as it used for the redwoods in the high Oakland hills, and not the round icons used for the encinal oak groves to the north, in West Oakland and downtown. Gary Lenhart, over at alamedainfo.com, suggests that this may mean there were redwoods here. I don’t buy that because the habitat is wrong and because I haven’t seen any mention of redwood groves along the shore, but the possibility is intriguing, especially since Friar Pedro Font, during the Anza expedition in 1776, also sketched the peninsula with a heavy forest (view west).

The 1857 Bache map doesn’t cover all of Alameda, but what it does show comports with the Beechey map in depicting a definite edge, not a marshy transition, between land and sea. This segment is from the west end; the Peralta Wharf was where Ballena Bay is today.

This map shows the entire peninsula forested with oaks and labeled “The Encinal,” which is how the first generation of Anglo occupiers knew it.

That’s all long past. The trees went early, turned into firewood and charcoal; the land was farmed, then subdivided for estates and divided again for homes. Underneath it all, the Alameda peninsula is a uniform body of windblown sand dating from glacial times, now surrounded by artificial landfill as seen in the geologic map. Nowhere is the elevation higher than 35 feet.

I should note an exception to that. Once upon a time the shellmound of Mound Street was the tallest thing in town, according to the monument in Lincoln Park. And here let me acknowledge that we live on Ohlone land, and that we don’t deserve the acceptance and welcome the tribes have granted us. Forgive us our trespasses.

Between the natural sand and the artificial fill are Alameda’s lagoons, the city’s most unexpected and hidden feature.

They’re hard to reach, mostly private land. In a few places you can see that the landward side is higher . . .

. . . and the Bay side is lower.

On Willow Street at Alameda Hospital, the transition is plain to see in the roadbed. This is the greatest topographical feature in the whole city.

The main body of the dunes is a very gentle dome, reaching just over 30 feet elevation along Central Avenue. It’s hard to catch in a photo, but charming to see in person. This is looking down Chestnut Street, on the north side of the dome, toward Round Top.

And in the other direction is the top of the dome, such as it is.

It just goes to show that, to a committed geologizer, every place has a there there.

Drunk on rocks

9 December 2019

Every now and then I come upon sights in the field that transfix me, that make me stop and stare, that suspend time. This is not uncommon with landscapes, of course — that’s why our phones are full of vacation pictures and why I have so many photos to share in these posts. It probably happens a lot less often with rocks, except among geologists and maybe not all of them either.

A few examples. It happened to me this spring at this sandstone roadcut on Bitterwater Valley Road west of Blackwells Corner.

Granite stoned me in the fall of 2006 just east of Donner Pass.

It happened to me in June 2012 a little west of Copperopolis. (I was bringing back a piece of this slate I’d taken two years earlier.)

One day in 2008 I found myself lost in the landscape of this ancient Nevada limestone.

And Oakland rocks can affect me that way too, like this serpentinite in Joaquin Miller Park’s native plant nursery did in 2010.

It can be a little embarrassing when you’re supposed to have your geologist’s eye engaged, and all you can do is stand there stunned. Being drunk on rocks is a subset of an experience I call field intoxication. Professionals need to get over the tendency, and teachers probably see their students fall prey to it, but I can let the high happen even in the presence of experts. That’s a writer’s privilege.

The last time it occurred, and gave me the topic for this post, was in Oakland this summer when John Wakabayashi, a leading figure in California geology and an Oakland native, accepted my invitation to visit some choice localities in his old home town. The finale of the tour was the pod of high-grade blueschist on the grounds of Mills College. I’ve featured it here before.

I knew he’d like it, and in fact he was delighted. He got animated. He climbed around, waved his hands and pointed out telltale features. He didn’t seem drunk at all. But while I noted what he was saying, I sat down dazzled into stillness. You see, this time the outcrop was clean after the spring rains and fully illuminated by the high July sun. I’d never seen it that way before. The rock shone blue as brilliant as the sky itself, and at all points it glittered with minute crystals and mineral flakes. All I could do was let this light wash over and into me, a sauna of stars. Knowing the camera was helpless to capture the moment, I didn’t attempt a photo. (Sorry.)

That’s getting drunk on rocks. Keep your eyes open and it might happen to you.