Forest of steles are all erected on the land. Only the "Baiheliang" in the north of Fuling, Sichuan Province is engraved with a stone fish 14 tail, and the stone carving 163 is hidden in the water. In the forest of steles, there are more than 30,000 words written by famous calligraphers in various styles, such as Kai, Li, Xing and Cao, as well as lifelike stone fish, white crane and Maitreya Buddha. It records the major evolution from Tang Dynasty to modern times 1200 years and dozens of low-water hydrological data in the upper reaches of the Yangtze River, which has become extremely precious historical data of social change and hydrological change. According to the statistics of inscriptions preserved on beams, "Stone Fish" appears once every 10 years, and every year it is harvested. What is the reason? We can use modern meteorological science to explain it. Originally, the carved carp was used as a fixed observation mark of the low water level of the Yangtze River, and its appearance was closely related to the climatic factors such as the height of the snow line on the Qinghai-Tibet Plateau and the rainfall in that year. However, the year when the "stone fish" came out of the water was suitable for rainfall, which was a good year for agricultural production. It is the working people's "draft zero" in ancient times.