The weekly weird
Cliff ‘lays’ egg-shaped stones!
Chan Dan Ya, Mandarin for ‘egg-producing cliff’, is a 19ft high and 65ft long cliff. It has an uneven surface but every three decades, it emits these odd-shaped rocks.
Residents in the nearby village, Gulu, have been scratching their heads for years as they keep finding perfectly smooth rocks. Natives of the village in China’s south-western Guizhou Province have observed for years how the eggs ‘incubate’ in hollow overhangs on the cliff and eventually fall to the ground.
Each hollow produces one egg every 30 years and the villagers believe the oval rocks bring luck and fortune. It is perhaps part of the reason why only around 70 of them have been preserved to date — the others may have been sold or stolen.
Geological tests done on the region showed that it formed during the Cambrian period, about 500 million years ago.
However, the specific section of cliff, which is part of Mount Gandeng, is made of calcareous rock that is common in many regions on Earth.
The difference in time it takes for each type of rock to erode has, therefore, been attributed to the appearance of the eggs, which comprise heavy sediment deposits, experts say.
This still does not explain how the rocks appear in smooth round shapes, or how a half-a-billion-year-old geological region managed to contain a calcareous rock formation.