Early Miocene; Extinct.
Original Description (from Dall, 1900, p. 1018):
"Oligocene of the Chipola beds at Alum Bluff and on the Chipola River, Florida; Burns.
Shell solid, ovate, inequilateral, the anterior side longer, beaks low, pointed; anterior end rounded, rather plump, posterior end more compressed, rostrate, strongly folded, dorsal area with two radial ridges, each with a shallow sulcus above it, posterior angle obliquely truncate; surface with obscure, fine radial striation, sculptured with strong, low, sharp, regular, elevated, concentric lamellae; hinge normal, left laterals obscure, lunule impressed, narrow, smooth; interior with an obscure thickened ray behind the anterior adductor scar; pallial sinus low, ovate, about half confluent below. Lon. 38, alt. 23, diam. 11 mm.
The left valve is very sharply pointed and flexed behind. This form may be regarded as a precursor of such types as T. interrupta Wood, of the recent fauna."
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