SHERIDAN, Wyo. (AP) -- Joshua Thomas got more than a history lesson during a recent visit to Montana's Little Bighorn Battlefield National Monument.

He discovered a piece of it.

The 13-year-old Sheridan boy was walking through the battlefield when he spotted a piece of leather near the trail that looked like a stick. Picking it up, he excitedly handed to his father, a Civil War buff.

Roger Coggins said he initially thought his son had found a belt loop, saying the piece of leather had been found right off the concrete trail and looked too modern to be an artifact.

"I wasn't sure at first we'd found anything at all," he said.

Upon inspection by historians, it turns out Thomas discovered an 1870s-era leather loop used to protect lariats from premature wear that was likely used by U.S. soldiers or civilians during the battle.

Soldiers and teamsters used lariats to picket their horses or mules when they camped. The ropes gave horses some freedom while they grazed, site historian John Doerner said.

Ranger Patrick Hill marked the site of the discovery last weekend while accompanying the family to the battlefield. Such finds are unusual, since the site has been thoroughly excavated, Doerner said.

"We extend our appreciation to Joshua for turning in the artifact," he said. It is illegal for such items to be removed from the site.

The piece may eventually be put on display, but currently sits in the site museum's collection of field specimens.

Like his father, Thomas said he enjoys visiting battlefields like the Little Bighorn and was shocked to learn he had discovered a piece of history.

"It's kind of neat learning new things," he said.

AP-WS-04-07-04 1120EDT