On the Oregon coast, science, legend, and wild theories are intertwined at Nehalem, where archaeologists, historians, treasure hunters, and crackpots attempt to dig out the past.

The Oregon coast is lined with cozy clapboard getaways, but the tranquil image of surf and sun is undermined by a small brochure in our motel room: “Tsunami Evacuation Map” reads the loud type against a bright yellow background. “If you feel an earthquake … DUCK, COVER AND HOLD,” it warns, like Cold War instructions for a nuclear attack.

The brochure includes a map of “assembly areas” to run for after you get out of your defensive crouch. Run like hell up hill: “A tsunami may be coming in a few minutes.” Have a nice weekend.

It’s a fitting reminder that this coast — beautiful as it is and dotted with tourist villages, parks, and scenic overviews — features a kind of rough trade too: huge storms, earthquakes, tidal waves, giant rocks, and killer waves. They don’t call the stretch on either side of the Columbia River the “graveyard of the Pacific” for nothing.

I recently stayed with a friend in Manzanita, 25 miles north of Tillamook and one block from miles of sandy beach. There are a dozen documented wrecks just off this shoreline, dating from the late 17th century to the early 20th. Those disasters are one reason I’m here.

The Oregon coast’s beauty has an edge. On this chilly May day on a beach just to the north, there are surfers black as seals in wetsuits braving the waves that batter the shore. But for others, the rocks and terrain present a challenge, a puzzle. Old men don’t throw their bodies into the surf, but into speculations about the mysteries of this place, and what the rocks, cliffs, stones, and driftwood can tell us about it.

Nearby Nehalem Bay is the site of a 16th century Spanish shipwreck that left evidence behind, specifically tons of beeswax that still occasionally washes up, as it has for the last 300 years (see “Unsolved Northwest Mysteries”). It also left shards of Chinese porcelain that were part if its cargo (typical of Spain’s Manila galleons), and Asian teak timbers that local residents have salvaged and used to make tables and walking sticks, or to repair their cabins. The Indians before them did something similar: If you go down to the Tillamook County Pioneer Museum, you’ll see Indian arrowheads made from blue and white china chips.

Before captains Cook and Vancouver or Lewis and Clark, Northwest Indians were using candle wax from the Philippines and porcelain from China brought to them, inadvertently, by an off-course Spanish vessel crewed by a multicultural complement of sailors likely including Spaniards, Filipinos, Malays, Africans, Chinese, and Mexican Indians. Here’s an early example of Pacific Rim cultural exchange.

Such anomalies are inherently fascinating, and often tied to others. As anyone born with the treasure-hunting gene understands, one thing leads to another, hopefully a pot of gold at the end of the rainbow. The surviving treasure from the Spanish galleon was mainly wax, a valuable commodity in its day and now a wonderful curiosity. You can see it in museums, sitting in glass cases looking like chunks of driftwood or old cheese rounds with moldy-looking rinds (maybe that’s just because we’re in Tillamook Cheese country). Some are stamped with Spanish shipping marks traced to the 1600s. But surely the vessel carried other treasure, perhaps gold and silver.

In fact, one small silver vessel that likely contained holy oil was found in the sand in the last century. It appears to be of Dutch origin, which adds to the picture of early “globalization.”

Today, archaeologists are trying to find the wreck, but more to satisfy curiosity and settle points of controversy. Which Spanish galleon was it? Did a Chinese junk wreck there, too? Can they find the galleon’s cannons? When exactly did the beeswax wreck occur? What is the geology of Nehalem Bay and the great spit of sand where the wreckage of the vessel was last seen in the mid-1920s? Will evidence of survivors ever be found?

Archaeologists are data-driven: they want to know the truth, gold or no. Besides, Oregon’s heritage laws are such that any shipwreck treasure would belong to the state. If it had wrecked in Washington, however, the loot could largely stay in private hands. Yet another example of the difference between the two states.

Other seekers, though, have been motivated by treasure pure and simple, and obsessed with the mysteries that inevitably go along with a treasure hunt. Looming over Manzanita and Nehalem is Neahkahnie Mountain, an impressive, forested headland that rises some 1,700 feet above the sandy beaches, with slopes that drop off to sea-cleaving cliffs where breakers crash and shorebirds wheel. If the beaches below are offering archaeologists bits of new information about a historic Spanish vessel, Neahkahnie Mountain teases with mysteries that might or might not be related.