Abstract
In the Herrera del Duque syncline, there is a large stratigraphic gap in the Middle Devonian that is located betweeen two lithostratigraphic units: García de Sola unit, and Abulagar Fm. Although they show lithological similarities, they are well differentiated. The García de Sola unit is described and informally established for the first time in this paper. It is the highest member of the Herrera Fm in the Herrera del Duque syncline. The more characteristic outcrop (“La Isla” section) is composed of several beds of quartzites and quartzitic sandstones with abundant iron oxide. This unit and the underlying one (upper member of the Herrera Fm.) have a paleontological record characteristic at least of an uppermost Emsian age for the beginning of the hiatus.The most probable cause of the hiatus is an emersion, as shown by the lithology of these units. Some brachiopods coming from these materials are interesting from the paleobiogeographic and biostratigraphic points of view; they are briefly described and figured.
