A sink counter at an airport toilet has been found to be completely covered in 439-million-year-old fossils after a travelling geologist went in to use the facilities and spotted the ancient remains.

Chen Shangbin, director of the Geology Department of the China University of Mining and Technology, was on a business trip when he paid a visit to the men’s room at Guiyang Longdongbao International Airport in Guiyang, China.

He noticed the patterns on the sink counter resembled fossil remains and took a photo of it, which he posted to social media.

The photo piqued the curiosity of stratigrapher and palaeontologist Dr Qian Maiping, who consulted with academics at the Chinese Academy of Sciences and Professor Shen Shuzhong of the School of Earth Sciences and Engineering of Nanjing University.

They identified the patterns in the sink counter as Paraconchidium shiqianensis, a type of Brachiopod dating back 439 million years.

Professor Shuzhong said in an educational TV programme on channel CCTV: “These shells contain many secrets of the Earth’s past, such as what was the environment then and what temperatures the seawater was measured at.”

The airport authorities confirmed they were aware the patterns were fossil remains and that they had purchased them as such.

According to Liu Liang, chairman of the Yingliang Stone Natural History Museum in Xiamen, China, since news of the airport sink counter went viral, the price of the fossil has surged from CNY 200 (GBP 22) per square metre (11 sq ft) to CNY 1,000 (GBP 111).