Tereñes Formation

The Tereñes Formation or Tereñes Marl is a Late Jurassic (Kimmeridgian) geologic formation in Asturias, Spain. The grey marls of the formation were deposited in a lagoonal environment at a muddy coast along a temporary inland sea. The lower section of the formation comprises silty and chalky sandstones with desiccation cracks and ripple marks, then becomes a bituminous, prominently ostracod-bearing, pelecypod shell chalk, lime chalk marl and marl. Fossil tracks have been reported from the formation.

Fossil content
The following fossils were reported from the formation:
 * Dinosaurs
 * Theropoda indet.
 * ?Allosauroidea indet.
 * Neosauropoda indet.
 * Ankylopollexia indet.
 * Crocodylimorphs
 * Dakosaurus sp.
 * cf. Machimosaurus sp.
 * Ichnofossils
 * Gigantosauropus asturiensis
 * Hispanosauropus hauboldi