PORTLAND (AP) - Portland is the only city on the West Coast to land a national exhibition of artifacts from the voyage of explorers Meriwether Lewis and William Clark, the Oregon Historical Society announced.

"Lewis & Clark: The National Bicentennial Exhibition" assembles - for the first time since 1806 - hundreds of artifacts and other pieces from the historic expedition.

The documents, plant specimens, scientific journals and practical tools of life will travel to Oregon for display Nov. 11, 2005 to March 11, 2006.

The schedule covers the explorers' time spent during a miserable, wet winter at Fort Clatsop on the Oregon coast 200 years ago.

The bicentennial exhibition, said Executive Director John C. Pierce, is unique. "There is simply no better way to understand the expedition's experience," Pierce said Thursday.

Included in the exhibit will be one of the few known original peace medals given out by Lewis and Clark in the course of the expedition initiated by President Thomas Jefferson.

To give the public a taste of the coming exhibition, the society on Thursday displayed a half-dozen rare pieces from its collection related to Lewis, Clark, Jefferson and the expedition.

They included a short letter in Jefferson's hand dated June 22, 1824, in which he politely responds to a request for his involvement in some project related to "the science of political economy."

"Worn down in body and mind by the weight of years," Jefferson wrote, he must leave such important questions to the younger generation.

The Missouri Historical Society organized the exhibit, which opened in St. Louis, has moved to Philadelphia and will travel to Denver before coming to Portland.