La_Caja_Formation
The La Caja Formation is a geologic formation in Mexico. It preserves fossils dating from the Kimmeridgian to the lower Berriasian.[1] La Caja Formation is widespread in northeastern and central Mexico and known for their abundant and diverse well-preserved ammonites. It was deposited in hemipelagic conditions, and predominantly consists of siliclastic sediments, including marl, with limestone.[2] It is laterally equivalent to the La Casita Formation, which represent more proximal facies.[3] The ichthyosaurs Ophthalmosaurus icenicus[4] and Parrassaurus yacahuitztli[5], metriorhynchid Cricosaurus saltillensis[6] and the giant pliosaur "Monster of Aramberri"[7] are known from the formation.