New Silurian brachiopods of the family Triplesiidae

The relative values of the characters of the members of the family Triple the characters of the ventral beak region and of the dorsal interior are used t those of the exterior to define the genera. Five genera, 2 subgenera, 18 sp are described; of these a genus, a subgenus, 16 species, and the variety are n scribed come mainly from the St. Clair limestone of Arkansas; one each f formation of Arkansas, the Criner formation and the Chimneyhill limest the Waldron formation of Tennessee, the Borkholm formation of Eston of Gotland.