The Moscovian is the second stage in the Pennsylvanian, the youngest subsystem of the Carboniferous. It is preceded by the Bashkirian and is followed by the Kasimovian. This stage overlaps with the regional European Westphalian stage, the North American Atokan and Desmoinesian stages and the Chinese Dallan stage.

A golden spike for the Moscovian stage has yet to be defined. The base of this stage is close to the first appearance of the conodonts Delinognathodus donetzianus, Idiognathoides postsulcatus, Streptognathodus expansus and Diplognathodus ellesmerensis or otherwise the fusulinids Aljutovella aljutovica, Profusulinella prisca and Eofusulina triangular.  

The Bashkirian-Moscovian Boundary Task Group proposed the fusulinoidean genus Eofusulina Rauser-Chernousova in Rauser-Chernousova et al. 1951 in evolutionary continuity with its ancestor Verella Dalmatskaya 1951 as a marker for this boundary (2010-2011 fiscal report).  However, a formal vote was not held. Fusulinoideans are rare in deeper water deposits. The base of the Moscovian can be approximated by the FADs of the conodonts Declinognathodus donetzianus and Diplognathodus ellesmerensis, and possibly by the FADs of advanced morphotypes of Streptognathodus expanses and S. suberectus(Qi et al., 2010; Bashkirian-Moscovian boundary task group reports for the 2010-2011 fiscal year).