The stones, many measuring several meters high and with one to three leveled surfaces, were discovered in a 2-km-long valley in Miaofengshan Town in Mentougou District, about 100 kilometers west of downtown Beijing.

"They should all have been the floating gravels of the Quaternary period," said discoverer Wang Hongjie, a senior engineer with the Beijing Municipal Hydrological and Geological Team.

Wang said the discovery of such a dense distribution of well-preserved glacial relics was the first one in northern China and also rare in the world.

Geologists say the discovery of the rare glacial relics will contribute to the study of how ancient glaciers formed and melted and their effects on the local climate.

Prior to the latest discovery, three sites of glacial relics had been found in Beijing but they only had sporadically distributed relics, they said.