Species: Valvata tricarinata

G - 200,000-2,500,000 square km (about 80,000-1,000,000 square miles) - G - Originally found in Quebec and New Brunswick west to Alberta and south to Wyoming, Arkansas, and Virginia (Burch, 1989); western occurrences are strongly disjunct and specimens from the WA and MT populations need to be compared in detail with more easterly occurrences, in view of the fact that speciation has occurred in several other genera with disjunct species swarms with both eastern and western representation. Recently, the species has been found in several lakes in the Clark Fork and Flathead drainages, Lake Roosevelt, WA, Ferry Co., WA, the Flathead Indian Reservation, MT; searches in ID turned up no sites (Frest and Johannes 1995).