The Taconic and southern Green mountains form a system of ridges drained by four watersheds in eastern New York and western New England: Lake Champlain and the Housatonic, Hudson, and Connecticut rivers. Ten species of mussels distributed among the Margaritiferidae and Unionidae are recorded, based on museum records and recent collections, from the area. The presence of species representing two regional faunas, the Mississippian and Northern Atlantic Slope, indicates that some western streams of the Taconic Mountain region were connected with both the Atlantic coastal and interior Mississippian drainages during the Late Pleistocene. However, a divide has persisted along the north–south trend of the two mountain chains that has prevented late glacial east–west migration between the Hudson River – Lake Champlain systems in eastern New York and the Connecticut River – Housatonic River systems in western New England.
Fish Communities and Habitat of Geomorphically Stable Reference Reaches in Streams of the Catskill Mountain Region, New York