Valvata tricarinata is a cold spring snail that today lives no farther south than Nebraska or Oklahoma. A common Pleistocene marker species in Texas Pleistocene deposits, this very small but distinctive aquatic snail was extirpated from the state at the end of the Pleistocene as groundwater temperatures increased. Recovered by fine-sieving of bulk matrix from stratum 2D. Source: Brown 2006(Fig. 8.72, A).