The tithonian (jurassic) ammonite fauna and stratigraphy of Sierra Catorce, San Luis Potosi, Mexico / Титонская (юрская) аммонитовая фауна и стратиграфия Сьерра-Каторсе, Сан-Луис-Потоси, Мексика

The Jurassic and Cretaceous of Sierra Catorce, which yielded the mol-luscan fauna for the first large paleontological monograph on Mexico (Castillo and Aguilera, 1895), comprises from the base: the Oxfordian Huizachal formation and Zuloaga Limestone and the Kimmeridgian to Tithonian La t aja Formation which is overlain by the Valanginian Taraises Formation. I he richly fossiliferous La Caja (— 53 m) is divided into two members. The I I Pastor Member, below, contains two condensed fossiliferous units, one near the base and one near the top; the El Verde Member, above, has sporadically distributed ammonite fauna. <...>