This mentioned taxonomy is an attempt to make an conclusive assignment from the different classifications of various scientists. Because the taxonomy may change due to the latest investigative methods and other findings, our map is a guide only.
H. G. Richards, 1962 - Studies on the marine Pleistocene: Part II. The marine Pleistocene mollusks of eastern North America - Transactions of the American Philosophocal Society (52), 1-142 (journal article, English)
H. G. Richards, 1947 - Invertebrate fossils from deep wells along the Atlantic Coastal Plain - Journal of Paleontology (21), 23-37 (journal article, English)