The Proveedora Formation consists of fine-grained quartzarenite with high bioturbation and trace fossils, it shows a low species richness (4) and evenness, where suspension feeders are dominating. The paleoenvironmental analysis of this unit indicates a sandy environment, such as a coastal and sublittoral areas, sandbars or delta front. The Buelna Formation is composed of limestone interbedded with shale, containing algae, brachiopods, salterellids, hyolithids, trilobites and echinoderms. Mostly it possesses a medium species richness (9) and intermediate evenness. Functional groups are dominated by primary producers and suspension feeders. The paleoenvironmental analysis of this unit indicates a shallow marine environment. The Cerro Prieto Formation consists of an oolitic limestone strongly recrystallized with few fossils, mainly brachiopods and trilobites. It has a low species richness (2) distributed in an unevenness way since only one species occupies the whole site. It indicates a shallow marine environment of high energy. The El Gavilán Formation consists of a thick sequence of shale interbedded with limestone, having abundant fossils like poriferans, brachiopods, hyolithids and trilobites, with a species richness (16) and with a high evenness, exhibiting a great variety of functional groups, dominating the suspension feeders and nektobenthic forms. The paleoenvironmental analysis of this unit shows an open shelf environment.