ROCHELLE Gardner wasn't expecting to find anything out of the ordinary when she took her dogs out for a walk one day last week.

With a day off that Wednesday, she put her two Jack Russells on leads and let them venture out into the expansive backyard of her home on Cranes Corner Road in Stafford County.

Without warning, one of the dogs hunkered down, the hair on its neck raised, and began growling and barking.

"I thought the neighbor's cat must be in the yard," said Gardner, who has lived at the home with her husband, Steven, since 1993. "But nothing quite prepared me for what had set the dog off."

Catching up with her pet, she saw a perfectly round, 12-foot circle in the grass, with defined edges where grass was dark or dead.

"Making it even more strange was the fact that the grass on the inside of the circle was all twisted around and flattened down," she said. "And neither of the dogs would go inside that circle."

Gardner, who raised three children at that home and considers herself to be both a religious and stable person, immediately called her husband.

"It looks like we have a crop circle in the backyard," she told him, half-joking.

His response: Better call the paper.

In the week since making the discovery, Gardner has passed on word of the strange circle to friends and family.

"When I tell them about it on the phone, they tell me I must be crazy or imagining something," said Gardner. "But when they come over and look, it leaves them just as confused and curious as I am."

No, says Gardner, she didn't immediately think of aliens, spaceships or some supernatural explanation for the circle.

But all the things she or others have suggested--spilled fertilizer or weed killer, lawn diseases, chemicals from her pool or septic system or some sort of vandalism--don't explain the circle.