The Meng-Yin or Mengyin Formation () is a geological formation in Shandong, China, whose strata date back to the Berriasian and Valanginian stages of the Early Cretaceous.
Dinosaur remains are among the fossils that have been recovered from the formation. The type material for the titanosauriform dinosaur Euhelopus was excavated at this formation by Otto Zdansky in 1923, in green/yellow sandstone and green/yellow siltstone that were deposited during the Barremian or Aptian stages of the Cretaceous period, approximately 129 to 113 million years ago.
Both the genus and species of Mengyinaia mengyinensis were named after the formation.
Vertebrate paleofauna
Indeterminate stegosaurid remains have been found in Shandong, China.
Other fossils
Mengyinaia mengyinensis
Fish
Sinamia zdanskyi
Paralycoptera wui
Lycoptera sp.
Reptiles
Ordosemys leios
Shantungosuchus chuhsienensis
Sinemys lens
Sinochelys applanata
?Dsungaripteridae indet. Stegosauria indet.