MARTINSVILLE, Va. (AP) -- Scientists with the Virginia Museum of Natural History have confirmed the discovery of a 500 million-year-old fossil called a stromatolite.

Officials at the Martinsville museum say the fossil was found at the Boxley Blue Ridge Quarry.

The museum says fragments and sections of stromatolites are fairly common, but it is very rare for a whole stromatolite "head" to be collected intact.

The specimen is the first-ever intact stromatolite head found in Virginia, and is one of the largest complete "heads" in the world.

Officials say the fossils are important in helping scientists understand more about environments that existed in the past.