An assemblage of several arthropods, mostly malacostracan crustaceans, but also including a mycteropid eurypterid, is described from the Heebner, Stark and Hushpuckney shale members of western Iowa and eastern Nebraska. These Upper Pennsylvanian black shales seem to represent a deep-water phase of a transgressive-regressive sequence. The arthropods are benthic forms, which apparently lived along the edge of an anoxic basin and were subject to catastrophic kills.--Modified journal abstract.