Shalamulun Fm

Central-Eastern Inner Mongolia. The naming section is located at the Baran Sof Platform, Inner Mongolia, and the reference section is located at Erden Obo, Siziwang Banner. Named by C.P. Berkey and W. Granger in 1923 and first described by Berkey and F.K. Morris in 1927.

Synonym: Shara Murun Fm, Xar Moron Fm

Mainly a sequence of grayish green mudstone and variegated or brick-red sandy mudstone, occasionally intercalated with sandstone lenses. The thickness is nearly 30m at Erden Obo.

Vertebrate fossils in this formation was first discovered by the Central Asian Expedition of the US New York Natural Historical Museum in 1922 and then sampled intensively by the expedition in 1923 and 1925. Afterwards, much work was done by the former Sino-Soviet Paleontological Expedition in 1959 and the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Geological Sciences in the 1970s. Many fossils were collected. Up to now, more than 30 mammal fossils have been reported. They are Gobiolagus tolmachovi, Shamolagus medius, Yuomys cavioides, Rhinotitan kaiseni, R. mongoliensis, Titan odectes minor, Deperetella cristata, Sianodon ulausuensis, Lushiamynodon sharamurenensis, Ulausuodon parvus and Archaemeryx optatus.

In comparison with the Irdin Manha fauna, this fauna has a rather small proportion of perissodactyles, especially tapirs, while an increased proportion of artiodactyles. From the composition of the entire fauna, this fauna is more advanced than the Irdin Manha fauna though some elements also appear in the Irdin Manha Formation. The age should be Middle Eocene.