Stone Age site reveals 'extraordinary' artworks

(CNN) -- Archaeologists in Russia have discovered an "extraordinary" group of Stone Age artworks which appear to have been carefully buried in pits and covered with mammoth bones, the researchers announced this week in a newly published paper.

At least some of the 21,000-22,000-year-old objects appear to have been regarded as magical, the scientists surmise.  The collection includes the only example of engravings of images found to date at the site -- what appear to be three overlapping mammoths only a few centimeters long and carved onto the rib of a mammoth.

"The main lines of the image are clear, not ragged; they were made by confident, unbroken movements," Hizri Amirkhanov and Sergey Lev write.  The carving may have been part of a hunting ritual, Lev told CNN.