Zhang Shi of the Song Dynasty told a story about the Shiyan in his Miscellanies of Tired Travel: "The Shiyan has Lingling, and the old one flies when it rains. I have tasted a sentence from Xie Langzhong: I learned the scriptures in my hometown Zhongshan Temple, and the high cliff is like a swallow, so I know it with my pen. The stone was violently attacked by the scorching sun, and suddenly there was a shower. People who know often fall to the ground and are cold and hot, so they can't fly. "

Here, Zhang Shi is writing down how Xie Ming, a little-known rural doctor, explained the field investigation and research process that Shi Yan could not fly. When he was studying in a village temple, he heard from his predecessors that Shi Yan could fly. In order to investigate this problem, Shi Yan was carefully observed for a long time. He first drew ten commandments on the rock with a pen ring to see if it would really fly away. Then, like a meteorological observatory watching the weather, he observed it. Later, he found that Shiyan finally landed due to the weathering of sun, wind, rain and water, especially the cracking of heat expansion and cold contraction, so he came to the correct conclusion that Shiyan could not fly.

The rock recorded in Yi Yan of Materia Medica in the Song Dynasty is like this: "Rock is like a boat clam, its color is like earth and its weight is like stone. How can you fly out without wings? His words are very close. " The book here points out that Shiyan is similar in shape to Meretrix meretrix, but it does not belong to Meretrix meretrix. That's right. According to modern biological classification, the swallow belongs to brachiopod, and the clam belongs to strontium petal. Although both of them are invertebrates and have two shells, the two shells of brachiopods are different in size and shape, and the two shells of Crapa branchiata are equal in size and similar in shape. It was not until 1853 that foreign countries recognized Shiyan as a marine brachiopod fossil.

The earliest recorded Ten Commandments in China began in the Jin Dynasty (the second half of the 4th century AD) with the famous painter Gu Kaizhi, who said in Enlightenment that "there are Ten Commandments in Lingling County". Later, Li Daoyuan (466 ~ 527), an outstanding geographer in the Northern Wei Dynasty, said in Notes on Water Classics: "Shiyan Mountain (now Qiyang, Hunan) is famous for its famous mountains. Its stone is big or small, if the mother and son are embarrassed. "

Later, in the Northern and Southern Dynasties, a man named Yin Keng wrote a poem about rocks, which mentioned the rocks in Lingling, Hunan. Now we know that the Devonian strata in Lingling, Hunan Province produce swallows.

In the Tang Dynasty, Shiyan was used as medicine. Li Shizhen, a pharmacologist in Ming Dynasty, listed Shiyan in Compendium of Materia Medica, and people began to pay more attention to Shiyan. Especially in many local chronicles. It can be seen that swallows are mostly found in Devonian strata, followed by Silurian strata (440-400 million years ago), and a few are found in Carboniferous and Permian strata (350-225 million years ago), belonging to brachiopod fossils. It has been found in the above strata in Hunan, Hubei, Guangxi, Yunnan, Guangdong, Jiangxi, Zhejiang, Jiangsu, Shanxi and other provinces. Chinese medicine shops all over the country have a complete Shiyan, and the price is also very cheap.