Abstract

Articulated specimens of Pentamerus oblongus and Stricklandia lens occur in a vertical position, umbones down, in blocks collected from a bed of late Llandovery age [Red Mountain Formation] in Alabama and from the Lower Llandovery of Scotland, respectively. These brachiopods are in their original position of growth, as indicated by growth irregularities in many specimens caused by proximity to their neighbors. Ample attachment surface was available in the form of disarticulated valves which are preserved just beneath the umbones of the specimens; the delthyria of these pentameroids are covered in such a way by the umbones of the brachial valves that it seems likely that their pedicles atrophied during ontogeny.

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