Ecological and statistical analyses of the Late Frasnian (Late Devonian) fauna of the Java Group of New York reveals the presence of three benthic marine communities. Using sedimentological and stratigraphic criteria, the Java Group may be divided into five physical‐environmental zones: nearshore marine, platform, prodelta, open shelf, and slope and basin. TheAmbocoelia‐ Cariniferella, Tylothyris‐Schizophoria. and Cyrtospirifer‐DouvillinaCommunities inhabited open shelf, outer platform ‐ prodelta, and inner platform ‐ nearshore habitats. respectively. Java species gradient curves overlap each other continuously, and species optima replace each other in a regular fashion along the onshore‐offshore environmental gradient. No evidence for competitive exclusion between species or sharp habitat discontinuities (ecotones) is seen for Java ecosystems. The same three‐fold division of communities, in equivalent habitats, can be seen in central Appalachian marine environments located approximately 500 km away along the ancient shoreline. The distribution of communities in this region appears to be directly related to the position and relative size of fluviodeltaic systems along the 500 km of ancient coastline.Palacoecology. communities, Braschiopoda. palaegeography. Devonian. Frasnian, Appalach