Elytha in the Cedar Valley Beds of Iowa

Abstract

In the Cedar Valley limestone occurs a group of brachiopods formerly referred to the genus Reticulana, but differing from Mississippian members of this genus, such as Reticulana cooperensis (Swallow), R. pseudolineata (Hall), and R. setigera (Hall), in several respects. Thus they tend to have a longer hingeline, a more strongly developed fold and sinus, more numerous and more closely approximated rows of spine bases and well developed radial plications, but lack double spines, as far as examination of available specimens shows. The Cedar Valley species, however, do have septa in the posterior portion of the valves. These differences are probably sufficient to remove these forms from Reticulana.