STONYCREEK -- Since United Flight 93 crashed into a field here eight years ago, more than 35,000 mementos have been left at the temporary memorial that honors the courageous crew and passengers who stopped hijackers from ramming the jetliner into the U.S. Capitol.

There are homemade crosses, rosaries, hats, flags, hand-drawn notes and poems, flowers, even a Spider-Man action figure and a stuffed snake.

"People have left their Purple Hearts, their Bronze Stars. There's a pair of combat boots that someone wore in Afghanistan," said Joanne Hanley, National Park Service superintendent of the Flight 93 National Memorial in Somerset County.

The art, artifacts and images that make up this spontaneous shrine, along with films and books about the people who sanctified this place, fascinate Alexander T. Riley, a Bucknell University sociologist.

Since 2004, the tall, engaging academic has returned often to study this homespun collection on a hillside that offers a distant view of the crash site. He is writing a book about creating the collective memory of Flight 93, noting in particular the sacred and secular symbols that Americans use to make sense of the terrorist attacks on Sept. 11, 2001.

During a visit here last month, Dr. Riley said the mixture of religious and patriotic symbols that people leave behind amounts to a kind of "civil religion," a phrase coined by his mentor, sociologist Robert Bellah.

In the United States, creating this civil religion entails blending Judeo-Christian narratives with patriotism. The result is powerful, Dr. Riley said, and "people feel more moved."

Biblical stories and symbols

More than 125,000 people visit the crash site every year to pay their respects. Among the objects left at the temporary memorial is a rough-hewn wooden cross partially wrapped in white cloth. Even many Americans who are not Christian recognize the cross and white cloth.

"When the cross has the shed shroud, we know that signifies resurrection and rebirth," Dr. Riley said. "Death took place here. Sacrifice took place here and yet, there was a resurrection.

"There's the idea of a Sept. 12 America. We'd been reborn. We had risen above the wreckage of those planes as a nation. We had this renewed sense that we would turn this tragedy into something that would make us better people," Dr. Riley said.

For many people, "Religion has done a very effective job of bringing order to the chaos of individual and collective death," he added.

But for others, the secular items, such as the Spider Man doll and stuffed snake, are "designed to say 'I was here.' "

But all the objects show, "how society makes sense of catastrophic events," he added.

People want to honor fallen heroes but how the nation ultimately achieves that goal often ignites conflict between urbanites and rural America, individuals and communities, atheists and believers, liberals and conservatives.

Two groups of people visit this site: "Those who want it to stay basically as it is, and those who are really supportive of the permanent design. These debates tell us about how we think about religious identity versus secular identity," Dr. Riley said.

Part of his research entails listening to 500 oral histories, which include interviews with visitors, who relate their memories of 9/11.

"Many visitors here have been to Ground Zero" in New York City. "They see the contrast right away. They like the temporary memorial in Somerset because of the religious iconography. A lot of people feel there should be Christian symbols at the permanent memorial, " the professor said.

His book will chronicle the design and building of the permanent memorial. He also will examine books by surviving family members, including Lisa Beamer, Deena Burnett and Lyzbeth Glick, whose husbands died in the crash, and Lisa Jefferson, the Verizon operator who spoke with Todd Beamer.

Those narratives, he said, are "part of the creation of collective memory."

Gifts for the dead

Unlike Mexicans, who take food and drink to graveyards on the Day of the Dead, Americans don't customarily offer gifts to the departed although they often plant flowers in cemeteries on Memorial Day.

Some of the offerings here are unforgettable: Among them a common, sand-colored brick that was broken in two with a note wrapped around it.

Barbara Black, chief of visitors services and cultural resources at the NPS office in Somerset, said if you saw it, "You wouldn't think much of it" and might wonder, "Was it there to hold down another tribute?

But the note reads: "This brick is from the compound of Taliban leader Mullah Mohammed Omar in Kandahar, Afghanistan. On Oct. 20, 2001, U.S. Special Operations Forces attacked and seized the compound. It is now used as a U.S. base from which attacks are launched against the Taliban and Al Qaeda and placed here in tribute to the first warriors of the Global War on Terror by members of the 19th Special Forces."

The note, left two years ago with the brick, "still gives me chills every time I read it," Ms. Black said. "You never know. The most common object left by someone could have incredible meaning. Sometimes it's a personal meaning that only they know about."