Sinuiju Formation

The Sinuiju Formation(신의주층) is a geologic formation in North Korea. Formerly of uncertain age, it is now thought to be Early Cretaceous. A variety of fossils are known from the formation, including those of anurognathid pterosaurs (possibly Jeholopterus) and birds such as the specimen of a very large enantiornithine with a 5 cm long tibia and a 3.5 cm long pygostyle. Frogs have also been found in the formation. Numerous compression fossils of insects have also been found.

Fossil content
Fish
 * Lycoptera sp.
 * Acipenseriformes indet.

Amphibians Pterosaurs
 * Anuran (a frog, might be referred to Liaobatrachus grabaui).
 * Jeholopterus cf. ningchengensis

Birds Dinosaurs
 * Confuciusornithidae indet. (Includes the fossil known colloquially as the Archaeopteryx of Korea)
 * Enantiornithes indet.
 * Ornithurae indet.

Dinosauria indet (tooth)

Mammals

Multituberculata indet.

Insects
 * Angarosphex baektoensus
 * Ephemeropsis sp.
 * Karataus ryonsangensis
 * Pompilopterus ryonsangensis
 * Sinuijuhelorus baektoensis
 * Sinuijus baektoensis
 * Stellularis sinuijuensis
 * Stenophlebia ryonsangensis
 * Sinuijumantispa ryonsangiensis

Other invertebrates
 * Eosestheria (a conchostracan)