Pennsylvanian invertebrates of the Mazon Creek area, Illinois: the Essex fauna and medusae / Ralph Gordon Johnson -- and Eugene S. Richardson, Jr. --
The essex fauna and medusae.
Johnson, Ralph Gordon,
Richardson, Eugene Stanley,
Field Museum Press ,
"April 18, 1968."
Fieldiana series has been published as Geological Series by Field Columbian Museum (1895-1909) and Field Museum of Natural History (1909-1943), and as Fieldiana: Geology by Chicago Natural History Mus
QE1 .F4 vol. 12, no. 7
Fieldiana. Geology ; v. 12, no. 7
Publication (Field Museum of Natural History) ; 1043