When Bertha, the massive drill worming through the waterfront, came to a halt last December, speculation took a turn for the surreal. What stopped the world’s largest tunnel-boring machine just 1,000 feet into its 1.7-mile journey? A locomotive buried 60 feet below the surface for a century had blocked progress on the $4 billion Alaska Way Viaduct replacement project, suggested one historian. Bertha bit into a submarine, a steamship, suggested others.

It looked to be the latest episode in a long-running series: Seattle, where progress and the past collide. 

Take, for example, just three years earlier, when crews digging near Paramount Theatre for another tunnel project—Sound Transit’s University Link Light Rail enterprise—exhumed an exquisitely preserved 115-year-old boxed sewer line, along with shoes, a beer bottle, a silver-plated spoon, and a ceramic cup. All were buried during the Denny Regrade, which ended in the early 1900s.

Or 1992, when work on a $579 million sewage-treatment plant in Magnolia stopped after surveyors unearthed two middens—ancient trash heaps that included decorative beads, bones, and stone tools—dating back some 3,600 years.

“People have lived in the Seattle area for thousands and thousands of years,” says Laura Phillips, archaeology collections manager at the Burke Museum of Natural History and Culture, which now possesses many of the above artifacts. “So these issues come up frequently.”

In a city growing as fast as ours—The Seattle Times recently reported that developers opened more apartments here in 2013 than in any of the preceding 20 years—we may never know how much has been lost. Despite laws protecting objects of archaeological import, our means of preserving the past before a Starbucks is built on top of it are hardly fool proof. 

Methods range from the sophisticated (archaeologists insert long auger probes into the ground, and construction crews work around any significant findings) to the seemingly chaotic (a hard-hatted archaeologist watches for historic swag as the backhoe bucket claws at the earth). The method employed depends on a number of political and economic factors, says Phillips, who cut her teeth as an archaeological consultant for the private sector and has personally eyeballed many a backhoe job. “The archaeology that goes on here is a compromise. It’s mitigation. It’s ‘Well, we’re going to destroy this archaeological site to put in this tunnel, so what do we do to offset that?’ ”

The state law protecting artifacts has only existed since 1975. Obviously major construction projects predate those protections, including the Alaskan Way Viaduct, which opened in 1953. “But really by then it wouldn’t have likely mattered,” says Scott Williams, an archaeologist with the Washington State Department of Transportation, which oversees the tunnel project. “Most of the [Native American] artifacts would have been lost when the city was originally formed” in the late 1800s, when settlers carted in sawdust and dirt—or fill—which covered the ancient tide flats.

What does often emerge are the things people left behind after Seattle became a city, like those recovered next to the Paramount and via initial surveys—in 2010—in the leadup to the Alaskan Way
tunnel endeavor. 

On a recent afternoon, Phillips stood before some of those objects in the basement of the Burke. She pointed to a metal wheel from a toy buggy, a horse comb, and a bottle that once contained dye for gray whiskers. The people who lived where the objects were found rarely show up in history books—prostitutes, longshoremen, immigrant laborers. And lately the things those people left behind have been overshadowed by the museum’s latest acquisition: the 20,000- to 60,000-year-old mammoth tusk found amid construction near South Lake Union in February. (Because it was a paleontological rather than archaeological find—and on private land—the developer who owns the site was under no obligation to report the fossil. The company could have chucked it in a Dumpster or used it for skeet-shooting practice, for all state law is concerned; it alerted the Burke out of a sense of civic responsibility.)

Phillips had an idea of what blocked Bertha in December. Or rather she had an idea of what it wasn’t. “I had to go look and see how deep it was”: 60 feet down, inconceivably deep for human artifacts in that area. (Her paleontologist friends suggested a glacial boulder.) “So I didn’t think it was going to be a human object.” 

Then, there in the basement, before all those trinkets, she laughed—at herself, reminded of what had in fact stopped the giant drill. Crews eventually discovered a length of steel pipe left by contractors in 2002.

“It really was human in the end.”