These dragon sightings were reported by Barsanuphius, a Russian religious at a hospital in China. He was told by soldiers that they had often seen a large dragon with wings entering and exiting a cave.
This happened in 1902. The information was passed on to Barsanuphius a couple of years later. It seems impossible to discover what this beast actually was. It may have been some kind of large winged lizard. Could it have been a pterosaur which didn't die off when he should have? At present, it remains a mystery.