Portland, Ore. ? The world may never know the precise location of a time capsule left by Teddy Roosevelt on a Portland hillside a century ago.

The Oregon Historical Society has decided against digging around a 40-foot monument to Lewis and Clark to see whether the time capsule — a copper box filled with relics — is buried there.

“It would be foolhardy,” said Norma Paulus, executive director of the historical society.

Questions about the location of the time capsule had created something of a scavenger hunt over the past few weeks.

The search started with an announcement that the former president’s great-grandson, Theodore Roosevelt IV, would come to Portland on May 28 to mark the 100th anniversary of the day his great-grandfather dedicated the Portland Lewis and Clark Monument.

But nobody knows where it is. Builders constructed the monument in stages over five years, with one stage often covering up the previous, making it hard for historians to figure out what’s underground and pinpoint where the capsule is.

People from across the country proposed ideas on how to locate it. A psychic from New York mailed the Oregon Historical Society a diagram showing the box’s supposed location. An engineer suggested banging a tuning fork against the granite monument and listening for hollow sounds. Engineers from several places recommended blasting the structure with a ground-penetrating radar to determine its location.

But the Oregon Historical Society is calling off the search.

According to Paulus, paying to dismantle parts of the Lewis and Clark Monument would cut into the organization’s education funds. And the society doesn’t want to do anything that would damage the monument.