The Maotianshan Shales (simplified Chinese: 帽天山页岩; traditional Chinese: 帽天山頁岩; pinyin: Màotiānshān yèyán) are a series of Early Cambrian sedimentary deposits in the Chiungchussu Formation or Heilinpu Formation, famous for their Konservat Lagerstätten, deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales form one of some 40 Cambrian fossil locations worldwide, exhibiting exquisite preservation of rarely preserved, non-mineralized soft tissue, comparable to the fossils of the Burgess Shale of British Columbia, Canada. They take their name from Maotianshan Hill (Chinese: 帽天山; pinyin: Màotiānshān; lit. 'Hat Sky Mountain') in Chengjiang County, Yunnan Province, China, and lies within the "Eoredlichia-Wutingaspis Zone" of South China. A 512-hectare (1,270-acre) site within this formation, known as the Chengjiang Fossil Site, was listed as a World Heritage Site by UNESCO in 2012.
The most famous assemblage of organisms are referred to as the Chengjiang biota for the multiple scattered fossil sites in Chengjiang. The age of the Chengjiang Lagerstätte is locally termed Qiongzhusian, a stage correlated to the late Atdabanian Stage in Siberian sequences of the middle of the Early Cambrian.The shales date to ≤518 million years ago.