Debra Thornton is worried that Smooch will be too friendly and Lilly too shy when they participate Saturday at Monticello in the 200th anniversary celebration of the Lewis and Clark expedition that opened the uncharted American West.

Thornton's Newfoundlands -- invited because the explorers took one of the breed as companion and guard dog on their trip from Illinois to what would become Washington state -- will be among the 4,000 guests expected at Thomas Jefferson's home to inaugurate a national, four-year commemoration of the trek ordered by Jefferson.

The dogs are being included because the organizers want to recognize all the participants in the remarkable adventure, including an Indian woman who guided the explorers; William Clark's slave, York; and the Indian tribes that befriended or fought with the Corps of Discovery.

Work on the celebration began about seven years ago, said Robert R. Archibald, president of the National Council of the Lewis and Clark Bicentennial, the nonprofit organizing group. Inclusiveness was important from the start and was extended to immigrant groups that located in the West as a result of the expedition, he said.

He said organizers were mindful of the disastrous 1992 effort to mark the 500th anniversary of Christopher Columbus's arrival in the New World. American Indians were excluded from its planning and staged a national protest against it.

The Monticello event is the first of 15 celebrations planned over four years at cities, towns and Indian reservations along the original trail. The events will be paid for with donations and proceeds from the sale of a commemorative coin to be issued by the U.S. Mint.

Saturday is the anniversary of the date Jefferson proposed the expedition in a confidential letter to Congress that complained of Indian resistance to the government's purchase of their land.

He warned that Indian opposition could prevent "an extension of territory which the rapid increase of our numbers will call for."

He proposed encouraging the Indians to take up farming, give up their nomadic ways and shop at government trading houses, where they could buy "those things which will contribute more to their domestic comfort than the possession of extensive, but uncultivated, wilds."

Congress approved the plan, and Meriwether Lewis, Jefferson's personal secretary, was chosen to lead an expedition to find a water route to the Pacific Ocean, document the lands newly purchased from France, and make friends with tribes along the way.

Lewis chose an old Army friend, Clark, to assist him. They set off from Wood River, Ill., on May 14, 1804, and returned to St. Louis on Sept. 23, 1806.

Half of the 60 tribes with a historic link to the expedition are cooperating with the commemoration. But Ben Sherman, president of the Western American Indian Chamber in Denver, said Native Americans are not celebrating.

"Historians set Lewis and Clark up as heroes," he said. "Not to us."

The forced removal of tribes from their land after the expedition to make way for white settlers is usually not part of the story, he said, but the commemoration gives Indians an opportunity to talk about the consequences for them.

Sherman takes particular issue with Lewis's description of his people, the Lakota Sioux, as the "vilest miscreants of a savage race," a sentiment that Lewis is not known to have reconsidered.

"Among us were many honorable people," Sherman said. "Our society was well regulated."

Yesterday at Monticello, the National Park Service unveiled its contribution to the commemoration -- a traveling exhibit in a recreational vehicle and a 150-seat tent -- the "Tent for All Voices." It will be used for Indian cultural performances and presentations by local communities along the trail.

Through Sunday, the Thomas Jefferson Foundation is sponsoring lectures at the University of Virginia and elsewhere on topics that include the contributions of Sacagawea, the Indian woman who was a translator and guide, and York.

According to a spokesman for Monticello, all the free tickets for Saturday's event have been distributed. The day will include a reading of Jefferson's letter to Congress and performances by the Lewis and Clark Fife and Drum Corps of St. Charles, Mo., and the Charlottesville Municipal Band.

Smooch and Lilly will be there, working the crowd with other dogs brought by the Colonial Newfoundland Club. Lewis's dog, Seaman, so named because he was purchased from a sailor who had brought him from Newfoundland, was valued for the strength and friendliness characteristic of the breed.

Roland Smith, author of a children's book on Seaman, said nobody knows whether the dog made it back to St. Louis.

Some believe so, Smith said, "but there is no evidence. Others, like me, think Seaman may have fallen behind on the return trip and never caught up."

This ceremony at Monticello is one of many planned to commemorate the Lewis and Clark expedition.Charles Clark, a descendant of William Clark, observes a Lewis and Clark event at Monticello. He is in costume for an event elsewhere.Debra Thornton's Newfoundlands will be taking part in a weekend Lewis and Clark celebration at Monticello.