Bay Farm Island

7 June 2021

The middle East Bay shoreline has three lumps in it, three bodies of ice age sand dunes that would seem more at home in San Francisco than over here. The first, the biggest, underlies downtown Oakland; as the city border signs say, it reaches an elevation of 42 feet right at City Hall. The second underlies Alameda, the former peninsula, and has a maximum elevation of about 35 feet. The third, smallest and lowest of all, barely over 10 feet, an accident of the modern sea level, is Bay Farm Island.

The Ohlone tribes came here to harvest shellfish from the tidal flats and bird eggs from the fields, although they apparently did not stay long or build shellmounds on the place they called Wind Whistle Island. The earliest maps show a small area of treeless land with marsh on three sides and a sandy bluff facing the Bay. This is Captain Beechey’s map, surveyed in the late 1820s.

The first USGS maps, from the late 1890s, accurately show the original island.

Like Oakland, the land was settled by squatters in the early 1850s, but instead of real-estate speculators they were farmers who quickly spotted the advantages of clean virgin soil, a high water table and easy access to the San Francisco markets. They did so well, this isolated patch got its name almost immediately. Bay Farm Island asparagus was famous — farmers cleared $500 an acre in Gold Rush dollars — and having grown it myself I can see how that crop would thrive in this excellent fine dune sand.

In the 1870s, efforts began to drain the marshes and turn it into hayfields and “made land.” A 1878 map neatly juxtaposes the old property lines on the natural island and the new speculator lots on the reclaimable land around it. The outline of the firm ground was a miniature of the Alameda peninsula, a baby slipper next to its parent as seen in the geologic map.


Thompson & West map, 1878 on davidrumsey.com

Maps from around 1900 show the island divided into large farm lots, with windmill-powered wells and long windbreaks planted against the prevailing northwesterlies. The twentieth century nearly erased all of this geography, as the former marsh was built up into the Oakland Airport, the Corica Park golf course and the Harbor Bay residential and business development. An overlay of the 1878 and current maps shows that there is no natural shoreline left.

Today Shoreline Park, at the western tip of the original island, is a manufactured shore on a high berm, armored with riprap. Inland, high residential walls and mature trees blunt the stiff wind off the Golden Gate.

But the pervasive landscaping and air traffic overhead can’t camouflage its eerie setting, a naked, remote, windswept place in the belly of the Bay.

What might Gertrude Stein, who famously bemoaned the loss of the Oakland she recalled from her youth, have said had she come instead from temporarily Bay Farm Island?

Read an excerpt from Eric Kos and Dennis Evanosky’s book on Bay Farm Island

Oakland, the city that borax built

24 May 2021

I was taking a bus ride and pondering what to write about for this post, when I looked toward Lake Merritt and found my topic written on the curb: “borax”.

This absurd-looking tag was surely a deeply historical reference to one of Oakland’s most memorable characters, Francis Marion Smith, who became the 19th-century version of a billionaire by exploiting the colossal borax deposits of the Nevada-California desert — and marketing based on the 20-mule teams that once hauled the ore to remote railheads. At least I hope it was, and not a new Oakland gang marking territory.

California is nicknamed the Golden State for the rare mineral that caused the Gold Rush — and the wildflowers too, of course — but Oakland sidestepped the Gold Rush and made its first wealth from the farms, orchards and oyster beds that fed San Francisco. (Its main geology-based industry was crushed rock.) A generation later, Smith became Oakland’s most influential citizen thanks to this boron-bearing mineral from the Nevada desert.

Boron is a cosmically rare element because stars can’t manufacture it, only high-energy cosmic rays that happen to strike oxygen or carbon nuclei in interstellar space. We are lucky that boron is rejected by minerals in the mantle and core and finds a home in the deep crust, mostly in the mineral tourmaline.


Schorl, or black tourmaline, is a boron silicate with a flexible formula that accommodates a wide mix of cations. Clear varieties are prized as gemstones.

In western North America, we’re luckier that crumbling continents and the volcanic activity that follows allow boron to rise to the surface, where it finds even more compatible mates and forms water-loving borate minerals in places like the dry lake beds of the Great Basin. The rise and fall of crustal blocks has decanted and concentrated all sorts of interesting minerals, from common salt and gypsum to lithium compounds and borates.

In the 1870s, borax (Na2B4O5(OH)4·8H2O) was an expensive compound well known to chemists, apothecaries and other specialists, but not at all a consumer good. Then Smith, a Wisconsin native drawn to the wild West, discovered a large deposit of ulexite (NaCaB5O6(OH)6∙5H2O) at Teel’s Marsh, in Nevada east of Mono Lake.


Fibrous ulexite or “TV rock” is available in any rock shop.

He’d seen enough mines by then to know what to do with it: refine it into borax, corner the traditional market for borax in chemistry and medicine, then sell the hell out of borax as the “foundation of a clean healthful home”: a disinfectant, insecticide, home remedy, and cleaning agent for fine clothing, now readily available to the person of ordinary means.

Smith succeeded in legendary fashion: his Nevada claim became the world’s largest borax mine, the first of many he operated, and a new industry was born from the abundance. That gave him the money to buy out his competitors as the opportunity arose and acquire their holdings in the desert. He grew rich; more than that, due to his marketing efforts — for instance, opening a borax shop in New York on Wall Street — he became known as “Borax Smith” at age 26 and, not long after, as “the Borax King.”

Smith moved from the Nevada desert to Oakland in 1881, where he proceeded to put his wealth to work, starting with a large estate and mansion in the Ivy Hill/Bella Vista neighborhood. As he gained experience building and running railroads to serve his desert mines, he consolidated the electric commuter rail lines of the East Bay under The Realty Syndicate, a land development partnership with Frank Havens. The Syndicate owned the majority of the high hills, developed many residential tracts around the Key lines, built the Claremont Resort and Key Route Inn, and planted the ill-fated eucalyptus plantations the length of the Oakland Hills, perhaps the city’s greatest ecocrime.

A hundred years ago, there was no more influential person in Oakland’s urban fabric than “Borax” Smith. The driven, meteoric entrepreneur was memorialized as the titular character Elam Harnish in Burning Daylight, Jack London’s most commercially successful novel: a man whose humanity blossomed not early with wealth, but later through love for a woman.

If only Oakland had borax deposits, or any boron-bearing minerals at all. But it doesn’t. I suppose if it had, Smith would have moved heaven and earth to turn that stuff into money. The only example I can show you is this tourmaline-studded ornamental rock from Pleasant Valley Court.

You might find some at a jeweler’s.

The pyrite orebody of Leona Heights

10 May 2021

Through historical accident (or fate), I’ve been a longtime reader of the late Oakland fiction author Jack Vance. As it happens, Vance was exposed to geology by coursework in mining engineering at UC Berkeley, and one of the most charming and memorable features of his Planet of Adventure series, written in the late 1960s, was the mineralogical currency of the planet Tschai, called sequins.

In volume 3 of the four-book series, we learn that sequins grow in a locality controlled by the alien Dirdir species, who amuse, enrich and feed themselves by hunting the sequin hunters. Sequins come in a range of colors, the clear ones being worth the least and the rare purple ones the most. I no longer have the text in front of me, but I remember them growing out of the ground, literally cropping out. Over at Tor.com, reviewer Paul Weimer does have (and loves) the text and reveals the additional detail that sequins consist of “a uranium mineral called chrysospine.”

The name is mineralogical fantasy, and possibly misleading in that “chryso-” refers to a golden or light green color. But come to think of it, uranium impurities often turn minerals brown from radiation damage, and radiation damage to an originally clear or golden mineral might result in a fair purple by analogy with “sun ripened” glass. An analogy with ripening fruit, too, is irresistible.

In populating his planet with this precious crystalline substance that grows in the ground like mushrooms, Vance evokes truly ancient geological notions that are natural among people who know nothing beyond the most basic alchemy. Gold Rush California saw a lot of that pre-industrial thinking among the amateur prospectors who scoured the state, and the Cornish miners who worked in the hard-rock Mother Lode mines brought along their own ancient customs and superstitions.

In Oakland, the people who exploited the pyrite in the Leona Heights mining district didn’t have the advantage of magic. But Fritz Boehmer, the canny Prussian immigrant who spearheaded mining in these hills, was apparently prone to dreams of earthly wealth, a deep California trait. He was not especially well educated, having apprenticed in metalworking. When he learned of the ore underneath his ocher deposit — one story is that he was digging postholes for a cattle fence, another that “a Japanese” was seeking water for a large fish pond — he thought he had an iron and copper mine, but the professionals set him straight. The copper was only a few percent (although later it was by-produced in paying quantities) and the iron was waste; the money from pyrite (FeS2) was in the sulfur. He let the Stauffer Chemical Company run the mines and gave scientists of the time free access to them.


Pyrite on quartz

The mines ran, interrupted by fires, for about 30 years starting in the 1890s. There were at least three of them. Records are confusing and I’m still trying to sort them out.

The best ore in Leona Heights was in pods of hard, dark, solid pyrite yielding 50 percent clean sulfur that sat, like layers of frosting in a chocolate cake, within a zone 12 to 30 feet thick that tilted into the hillside. The people who published papers about this district scratched their heads at the deposits. They all concluded that the Leona volcanics (“Leona rhyolite” as they knew it) was so jammed with pyrite that the upper part weathered into iron oxides (which stayed behind as the ocherous “iron cap” or gossan) and iron sulfate, which leached down in solution and was reduced back to pyrite beneath the water table in the so-called vadose zone, where it was exposed to a lot of carbonaceous material.


Fine-grained pyrite concentrated in the Leona volcanics, Campus Drive

The trouble with the kind of intermittent research these geologists pursued in the operating mines is that each person who visited the workings saw a different set of rocks. The Leona Heights mines were also prone to fires, so parts were off limits for years at a time, or abandoned.

Henry Mulryan, in a 1925 Master’s thesis, summarized the previous work and consulted their authors, but with several parts of the mines closed off by fires he failed to find any of that carbon-rich rock in the areas he had access to. Unable to prove anything one way or the other, he was forced to punt, saying he would rather wait and see what further digging revealed at depth. “If the Leona Orebody is derived under vadose conditions, then it is the only one known to the writer and should take its place in the world’s literature on ore deposits.” (I too am skeptical about this carbonaceous rock, but the Oakland Hills are complicated here so who knows?)

That was a hundred years ago, before geologists made huge strides in understanding this class of “volcanogenic massive sulfide deposit,” not to mention a scientific revolution, in the years between then and now. Meanwhile the mines are long closed and will never be reopened. The samples, if they still exist, are gathering dust in obscure cabinets. I’ve read all the contemporary literature (except for some theses — Leona Heights seemed to be a handy subject for Stanford and Berkeley students at the time), which is an absorbing chore because the records are sketchy by modern standards and the terminology has changed. But there are rewards; Mulryan had some good photos of the Leona sulfur mine circa 1924.


Looking west on the Leona Mine. The hook in the road is at the end of McDonell Avenue. The rail line carried ore cars to the crusher, then to a 1600-foot aerial tram that carried the ore to the train in Laundry Farm canyon. Chabot Observatory in the background.

I’m still scratching my head about the Leona Heights pyrite, and I find myself envying Jack Vance’s freedom of imagination. Reality can be tough; you can’t just make up something wonderful.

The twilight of California oil

26 April 2021

Last week the governor ordered a state agency to stop issuing fracking permits to oil drillers, starting as of 2024. This is less of a big deal than it seems. Hydraulic fracturing is rarely used in California because the permitting process was tightened in 2014 and because our earthquake-shaken rocks are already well fractured, and only three oil districts do it at all, accounting for about two percent of the state’s production. One place they still do it is in the Lost Hills area, which is fun to drive through if you like taking pictures like this:

This change won’t affect the California oil industry much, but it sounds great and is worth doing.

The governer also ordered another agency to start plans to shut down all oil production in California as of 2045. This is a big deal. Oil is as much a part of California as gold, Shasta and the redwoods. But our oil production has dropped by half since 1985, and now’s the right time to set a deadline. According to a pair of fresh studies, it won’t even start to hurt business for another decade.

Time to start saying goodbye to our old friend.

Natural seeps of oil and asphalt occur all over the state. The one at McKittrick is famous among geologists.

The tar glaciers at Carpenteria State Beach, near Santa Barbara, are a real spectacle.

These materials were used by the native tribes for things like sealing baskets, waterproofing boats and medicine. I’ll bet they made torches with them too.

Americans mined the deposits at first and distilled kerosene from them. That was a dirty business. Starting in 1860, enterprising men tried drilling wells like the first successful ones in western Pennsylvania. The first California oil well to make a profit was drilled in 1876 near Newhall, and we were off to the races.

Petroleum, oil from the ground, was a huge advance. It meant we could stop leveling forests for firewood. It meant we could stop the deadly, wasteful business of hunting whales to make liquid fuels or roasting coal to make gas. No one knew it at the time, but we could invent plastic. The petroleum-based energy and chemical system was eagerly adopted, popular and universal. But today we know how to do even better without it.

As always with this blog, there’s an Oakland angle. The Bay area is oil country.

There are oil seeps in Wildcat Canyon, and the first oil well in the Bay area was drilled nearby, east of San Pablo, in 1862. A short-lived oil field in Orinda, at the Minor ranch on Lauterwasser Creek, pumped greenish crude in the late 1890s. Oakland boosters like H. A. Aldritch, in 1897, were sanguine: “For many years oil has been oozing out of the shale and sandstone formations, and in every instance this oil has been strongly impregnated with gas. That the near future will produce this most promising industry, affording cheaper fuel for manufacturing purposes, is a settled fact. My prediction is that within the next few years Oakland and other cities and towns of this county will be in the full enjoyment of this, one of nature’s greatest blessings.” He was right, but the profitable wells were in the Central Valley.

A large portion of California’s oil originates in the Monterey Formation, a body of ribbon chert found up and down the coast. Oakland has a thick stripe of its close sibling, the Claremont Shale, running through the high hills.

Wherever you see it, it’s generally bleached-looking like this, but underground it’s black with organic matter, from the diatoms whose microscopic silica shells are what make up chert. Diatoms manufacture and store drops of oil inside their shells to help them float, and that oil is what becomes crude oil after cooking underground for geological periods of time.

When the Caldecott Tunnel bores were being dug, oil and gas wafted off this chert and caught fire more than once. During excavation of the fourth bore a few years ago, nothing that could spark was allowed inside. So let it be known: Oakland’s hills are full of oil. I have yet to find an oil or gas seep here, but it’s on my list. I have a theory that one may have had something to do with the great fire of 1991, which burst out in an area where the Claremont Shale is deeply exposed.

Here or wherever, petroleum will always be something to reckon with in California. But we have to start leaving it in the ground at all costs and return it to being a geological curiosity.