It was 68 years ago a Colorado farmer building an outhouse found something that might have changed Western history.

About 8 feet down, Tom Kenney found a flat, precise mosaic of evenly spaced rectangular and square sandstone pieces apparently grouted with a putty-like substance covering more than 12 square feet, the Denver Post reported Wednesday.

Some archaeologists subsequently said it was undisputable evidence of an advanced civilization 25,000 to 80,000 years ago. Others said they were sure it was the work of nature.

The floor was eventually reburied until recently, when more scientists examined it and concluded nature was responsible, maybe.

Larry Luebke, a retired geologist, told the Post what appeared to be 4-inch-thick tiles carefully cut, leveled, and grouted actually were pieces of bedrock, evenly cracked and naturally grouted by bentonite clay 40 million years ago. He said its polished appearance came after being exposed to the elements for tens of thousands of years.

"This would have turned Western history on its head," Dave Bailey, curator at the Museum of Western Colorado told the newspaper. But even Bailey admits he still has some doubts about the floor's origin.

Copyright 2005 by United Press International