Stanton, T.W.; Hatcher, J.B. (1905). Geology and paleontology of the Judith River beds. <em>United States Geological Survey Bulletin.</em> 257: 1-123., available online at https://pubs.usgs.gov/bul/0257/report.pdf
page(s): 117, pl. 13, fig. 4 [details]
basis of record
Henderson, J. (1935). Fossil non-marine Mollusca of North America. <em>Geological Society of America Special Papers.</em> 3: 1-313.
page(s): 220 [details] Available for editors [request]
From editor or global species database
Type locality "In the fresh-water beds of the Judith River on Dog Creek and at other localities near Judith, Mont., on Cow Creek, and on Milk River from Havre to the Canadian boundary. [...] from Simpson's ranch, on Milk River about 10 miles south of the boundary", Montana, United States; Judith River Formation, Campanian, late Cretaceous [details]