What’s the oldest stone in Seattle? What's the best place in town to see fossils outside of the Burke Museum? Why do the rustic sandstone ledges, pediments and bases on so many old buildings seem to be peeling away? What do Seattle’s Rainier Tower, New York’s late Twin Towers, Rome’s Coliseum and Venice’s Piazza San Marco all have in common?
Most of us don’t think to ask such questions, though we walk past the answers every day. We look at buildings and we see buildings. We look at stones, we see stones. David B. Williams looks at buildings and sees stones. He looks at stones and sees stories.
Williams, a local geologist-turned-writer, has carved out a niche as a chronicler of the stones that cities are built of, a sort of mineralogical Arthur Lee Jacobson. Like a good specialist, he displays a boundless zest for such matters as prehistoric calcite deposition, ancient travertine transport and 20th Century slate-roof economics, and he has a bottomless well of stories about them, which fills his books Stories in Stone: Travels Through Urban Geology and Cairns: Messengers in Stone. At book length that may be more rocks than a casual reader wants to break, but such tales are the stuff of a great walking tour, which is what Williams offers now and then through downtown Seattle.
Growing up a rock hound in Seattle, as Williams did, means going against the local grain. Our glacially tilled ridges and valleys have fewer big rocks than just about any other terrain outside of alluvial muck. And the most distinctive materials on our older buildings are their extravagant terra cotta (“baked earth,” ceramic cladding and ornamentation) and, in such buildings as the Seattle Tower and old Public Health hospital, their subtly modulated, colored bricks.
But even those human-made materials reflect the city’s geology and geography. The fine-grained local clay was especially good for terra cotta, and the city’s ready shipping access helped it become a major manufacturer and exporter of building bricks. Doubtless there are many brick stories to be gleaned here, but Williams is still looking for the brick nerd who can impart them — the brickyard equivalent of the local geologist David Knoblauch, “a real scholar of local stone” and valuable source for Williams.
Still, there’s no shortage of terra cotta lore: The eight “Indian chief” heads on the 1910 Cobb Building (at Fourth Avenue and University Street) may look generic, but they were supposedly modeled after a photo portrait by Edward S. Curtis. The tusks on the walrus heads adorning the 1916 Arctic Building (Third and Cherry) are actually replicas, installed nearly 50 years after the 1949 earthquake dislodged several of the originals and the rest were removed; perhaps they’re still sitting in some civic warehouse, next to the Lost Ark. A legend widely reported as fact has it that they were actual walrus tusks, but Williams has found no evidence of that. Even then ivory was too valuable to stick on buildings.
When Seattle needed building stone cheap and fast, as when it rebuilt after the 1889 fire, it naturally turned to the nearest sites with serviceable stone and ready rail or barge access. Unfortunately, the stones thus obtained — Chuckanut, Tenino and Wilkinson sandstone and Index granite — are rather bland grey stuff. The sandstones are also prone to erosion, especially where hasty or ignorant builders set them with their grain running perpendicular to the ground, which allows water to get behind their sedimentary layers and peel them off like sloughing skin. (Not all sandstones are created equal, however; the pietra serena sandstone in Florence’s churches and palaces has endured serenely for many hundreds of years.)
You can see the peeling at work in the rusticated stone base of the 1890 Holyoke Building (First and Spring), one of the first office buildings to go up after the fire. “I think that’s really cool,” says Williams, always glad to watch a geologic process at work. Seattle’s builders evidently weren’t so appreciative; they soon cast around for sturdier and showier stones. For the street-level cladding (pictured here) of the 1929 Exchange Building at Second and University they also reached back — way back, some 3.5 billion years — for a stone as old as the earliest known evidence of life itself: granite-like Morton gneiss from Morton, Minnesota (“the oldest stone you’ll ever see,” claims Williams). It’s set off by elegant black Portoro limestone from La Spezia, Italy, just a few miles from the renowned (and in Williams’ view overrated) marble quarries of Carrara.
Seattle builders may boast when they use Carrara marble, but they’ve turned more often to the much nearer Alaskan marble that clads the Smith Tower, atop a base of homey Index granite. In time, however, they shed regional biases and brought stone from farther afield. Often they turned to America’s good, gray default building stone: Salem limestone from Indiana, notably visible at the Seattle Art Museum and Rainier Club (Fourth and Columbia). This limestone, like sandstone, is a sedimentary rock, but it’s quite robust. With virtually no grain, it can be turned any which way to the weather without peeling. And it was cheap. So many post offices — about 750 of them around the country — were built with Salem limestone that congressmen from other states tried to ban it to give their constituents' quarries a chance.
Ogling fossils at the Rainier Club. Credit: Eric Scigliano
Seattle’s most celebrated homegrown architect, Minoru Yamasaki, preferred Tivoli travertine, quarried near Rome and heavily used in the ancient city. Travertine is limestone formed in hot springs, such as Yellowstone’s Mammoth Spring. Their bubbling gases leave distinctive, grime-collecting wormhole-like pits — an ironic outcome to a hot bath.
Travertine’s rapid precipitation out of those chemical pressure cookers makes it dense and sturdy. Stones pilfered from the Coliseum, the world’s largest structure built (rather than clad) with travertine, still pave the Piazza San Marco in Venice and untold Roman churches. Yamasaki’s most famous travertine-sheathed creation, the World Trade Center’s twin towers, did not last even one 50th as long as the Coliseum. The clock’s still ticking on his local Rainer Tower (Fourth and University).
Travertine can be a motherlode of fossils. Williams jokes that once you see the splendid imprints in the gleaming travertine walls of Los Angeles’s Getty Center, you needn’t waste time on the art inside. Or maybe he’s not joking. I’ve heard him elsewhere say that “art is bullshit.” But Seattle’s prime prehistoric specimens are found in other building stones.
The oldest fossils at the Rainier Club aren’t snoozing in the easy chairs inside, they’re embedded in the low wall of Salem limestone that rings the building, a soup of tiny 330-million-year-old crinoids, corals, bryozoans, brachiopods and clam-like bivalves. Williams concludes his weekend tours there, whipping out a batch of magnifiers for close examination — to oohs and ahs.
But even that’s not the best fossil show in downtown Seattle. The lobby, rest rooms, elevator cars and who knows what else of the Grand Hyatt Hotel at 721 Pine Street are paved in an oatmeal-colored, 175-million-year-old stone called Treuchtlingen marble, after a spot in Germany where lots of it is quarried.
It may come from Treuchtlingen, but it’s actually a limestone, not marble. The difference is one of formation rather than chemistry. Both types of stone are composed of calcium carbonate from the shells of ancient sea creatures. Marble, a metamorphic rock, is what sedimentary limestone becomes when it gets kneaded, folded and squeezed. Elegant limestones often get hyped as “marble,” just as Rainier Beach becomes “Columbia City” in the real estate ads.
But limestone, being rawer, often preserves more traces of the organisms that made it, especially the Treuchtlingen. Pencil-sized crinoids and sponges big enough to scrub the dishes swirl so exuberantly across the creamy tan surface you expect the staff to come tell them to keep it down.
These ammonites once ruled the seas. Credit: Eric Scigliano
A desk clerk hurried over, but only to trade paleontology notes. “I heard you say ‘ammonites’!” he said, grinning. These biblical-sounding mollusks, sectioned spiral shells that look a little like today’s chambered nautilus but are more closely related to octopuses and cuttlefish, ruled the seas till bony fish evolved and outswam them. They still rule the Grand Hyatt lobby (look to the left of the front desk), time travelers from an almost unimaginably distant age, brought close by the stone workers’ cutting and polishing.
Looking at stones makes time travelers of us all. Once you start, you may never look at the city in quite the same way. Its buildings may be born yesterday, but they’re windows to far-off pasts.
David Williams will conduct his next “Hidden Geology of Seattle” tours on December 6 at 10am and 1pm. More information here.
