The identification of fossils from 16 new localities on southwestern New World Island has resulted in the refinement and simplification of local stratigraphy and in the correlation of rock units across an intensely deformed area. Complex stratigraphic classifications of earlier workers are replaced by a simpler scheme consisting of four formations: the Summerford Formation (oldest), Rogers Cove Formation, Sansom Formation, and Goldson Formation. Mélange units are fault related and cannot be included in the stratigraphy. Fossil and lithological data provided here confirm previous indications that the rocks of the Summerford Formation are the remains of a long-lived volcanic-island complex. This complex is overlain by a markedly diachronous coarsening-upwards sequence of marine clastic sediments, now represented by the Rogers Cove, Sansom, and Goldson formations.The new stratigraphic data, combined with structural evidence, indicate that the stratigraphy is repeated across several bedding-parallel faults. Significant diachroneity of formation boundaries and the absence of syndepositional high-angle faults suggest deposition in one large mid-Paleozoic basin rather than in a number of small dynamic basins.