The following data files are fossil collections (rows) by genera/morphotype (columns) for a series of third-order depositional sequences in Late Ordovician-Early Silurian strata of the Cincinnati Arch, Ohio and Kentucky. Each cell records the abundance (number of individuals) for each genus in that collection. Full counting protocols are detailed in Holland and Patzkowsky (2007). Steven M. Holland and Mark E. Patzkowsky collected the C1-C6 data in the Late Ordovician strata of the Cincinnati Arch. These are the original raw, unculled data. Genera are often represented by short-hand names. Full names can be seen in the original publication or down to the species-level in the associated files at the paleobiology database (www.paleodb.org; Publication ID: 24429). Andrew Zaffos collected the B1 data in the Early Silurian strata of the Cincinnati Arch. This is the original raw, unculled data. The full names of genera are included in the data file and there is no corresponding dataset at the paleobiology database. C1: Clays Ferry and Kope Formations C2: Tate, Garrard, Calloway Creek, Bellevue, Miamitown, and Fairview Formations C3: Terrill, Gilbert, Mount Auburn, and Coryville Formations C4: Rowland, Sunset, Oregonia, and “Sunset” Formations C5: Saluda, Whitewater, Liberty, and Waynesville Formations C6: Upper Whitewater and Elkhorn Formations B1: “White” and “Red” Brassfield Formation S. M. Holland and M.E. Patzkowsky. 2007. Gradient ecology of a biotic invasion: biofacies of the type Cincinnatian Series (Upper Ordovician), Cincinnati, Ohio region, USA. Palaios 22:408-423 [S. Holland/S. Holland]