Discovery of the fossils of Chengjiang

Mr Xian-guang Hou of the Nanjing Institute of Geology and Palaeontology had been working for very many years in the field. His ongoing quest was for stratigraphic deposits containing fossils of bradoriids (an ancient bivalve arthropod) from the early Cambrian which is his specialty. In June 1984 he began systematic sampling of an exposed layer on the west hills of Mao-tian Mountain in Chengjiang County, Yunnan Province. After discovering two unusual fossils, he found a Naraoia, a fossilized arthropod only previously seen in Burgess Shale in Canada. It was on the face of a crack in the rock and the specimen included both the anterior and posterior shields of Naraoia). Several mollusk fossils not previously found were also discovered, including: Leanchoilia, Brachiocaris, Heliomedusa, and Maotianshania. Additional fossils in new categories were also found in subsequent investigation and studies; this is how the 530 million year old Chengjiang fossils were accidentally discovered.