Amga Layer

Amga Layer

 

(named for the Amga River, left tributary of the Aldan, in Eastern Siberia), the lowest layer of the middle section of the Cambrian system. The name was suggested by G. F. Gurari in 1950. The paleontological justification for the name was given by N. V. Pokrovskaia and N. E. Cher-nysheva. A typical section of the layer is composed of limestones and is characterized by a complex of trilobites of the families Oryctocephalidae, Paradoxididae, and others. It occurs widely in Siberia, Kazakhstan, and Middle Asia; analogous layers are known in western Europe, North America, China, and Australia.