The summer sun had started to set on a clear, cloudless day. The water was calm as three men pushed their boat closer to the rock face. A few fishing boats floated nearby.

Then all three men began screaming.

"It was only moments later we realized we had broken the rules of proper boating etiquette," said Francis Scardera. "We were all standing in the boat. And we were so loud in our excitement, it appeared we upset people" fishing nearby.

The Canadian high school archaeology teacher and his two friends had found a rare example of Indian rock art long thought to have been erased by decades of weathering. Scardera reported his find for the first time this fall at the Conference on Iroquois Research at the Rensselaerville Institute Conference Center.

The red ochre-streaked rock face was last recorded in a 1920 photograph kept by the New York State Museum in Albany.

"The photograph very much resembles what's out there today," said State Archaeologist Christina Rieth. "If it is the same pictograph and it's still intact, it would be a pretty amazing find."

"Picture rocks are extremely rare in the Northeast," said Ed Lenik, one of the leading authorities on Native American rock art in the Northeast and author of "Picture Rocks: American Indian Rock Art in the Northeast Woodlands."

"This is a very significant discovery," he said. "You're talking about an organic material that's hundreds of years old and still there."

There are only two other known Indian pictographs in existence in the Northeast -- both in Maine -- and the only other known site in upstate New York was the "Painted Rocks of the Mohawk," near Amsterdam, which have long been lost to history, said Lenik, who runs a cultural research survey business in Wayne, N.J.

"It's extremely important for this site to be protected and preserved," Lenik said.

For the past seven summers, Scardera, who works at Loyola High School, a private, Jesuit school in Montreal, has moonlighted as a crew chief for a Colorado State University research team. The team is helping Army officials at Fort Drum search for any important archaeological sites that could be disturbed by ongoing construction to prepare for the infusion of 6,000 new soldiers.

Whenever there is construction on federal land, it must be checked for any historic value first, Fort Drum Chief Archaeologist Laurie Rush said.

"It's a very impressive panel," said Rush, one of only about a dozen scientists who have seen the rocks and know their locations in the Indian River Drainage Basin in St. Lawrence and Jefferson counties.

"It's an exhilarating find. We're thinking if there's rock art there, there could be rock art here," she said. Fort Drum covers more than 107,000 acres, much of it wilderness, and Rush and her small staff have already identified dozens of significant Iroquois sites on the post, including villages and a quarry.

Over two summers, the 38-year-old Scardera used his free time to search for the pictographs. Aided only with the state museum photograph, historical accounts and aerial photos, he narrowed the possible locations. Scardera said the drawings were so well hidden that the people who had owned the property for the past 15 years weren't even aware they were there.

Scardera said it appeared most of the pictographs are concentrated on a single limestone and sandstone panel, about three feet above the water. Pictographs are difficult to date, even when they display discernible images, he said.

"Unfortunately the images have slowly faded over the years -- effects of the elements. The images that have survived are difficult to decipher, and any attempt in identifying them at this stage would be pure speculation," said Scardera.

One unique characteristic is that the early artists incorporated the natural crevices into their work. "There is a possibility they may be pre-contact," Scardera said, referring to the period before European explorers arrived.

The artists' identity is also a mystery, he said. Artifacts from the Oneida and Mohawk cultures -- members of the Iroquois Confederacy -- have been found in the area, in which both tribes lived at different times.

But the Oswagatchie Indians also lived in the area and Algonquins were known to have passed through, he said.

"One can't rule out the possibility of more than one group making additions to the rock face, much like our modern-day graffiti artists," Scardera said.

The pictographs were first noted in 1853 by Franklin Hough, a New York-born physician, scientist, historian and statistician who is regarded as the "father of American forestry." The pictographs were photographed in 1920 by state archaeologist Arthur C. Parker and published in a 1922 State Museum bulletin.

Scardera is convinced that there is more rock art to be discovered in ancient Iroquoia, a region that covered most of present-day New York, Pennsylvania and the southern parts of Quebec and Ontario.

Indian rock art is plentiful in the American West and Southwest, where settlement and development came later and archaeologists had a head start on discovering and saving sites, such as Chaco Canyon in New Mexico and Barrier Canyon in Utah.

Lenik said it's likely that many rock art sites existed in Iroquoia but they have been lost to the elements and three centuries of development. As a result, there has been little research done over the years on rock art by Indians in the Northeast, said Lenik, who has hunted rock art sites for a quarter-century.

Lenik also thinks there may be fewer sites because Indians in the Northeast practiced their art skills, painting and carving, on trees -- dendroglyphs -- rather than rocks.