The Mesozoic successions of Rajasthan and Kachchh represent some of the most important geological records of western India and provide valuable information regarding sedimentation, palaeoenvironments, and tectonic evolution during the Triassic, Jurassic, and Cretaceous periods. These successions are well exposed and have been extensively studied for their stratigraphic, palaeontological, and economic significance. The stratigraphy of these regions reflects deposition in varied environments ranging from continental fluvial systems to shallow marine settings. In Rajasthan, the Mesozoic rocks are mainly developed in the Jaisalmer Basin and adjoining areas. The succession begins with the Lathi Formation, which is considered to be of Early Jurassic age. This formation is composed predominantly of sandstones, shales, and conglomerates, indicating deposition under continental to marginal marine conditions. Above the Lathi Formation lies the Jaisalmer Formation, which is one of the most significant fossiliferous units of the region. It consists mainly of limestones, calcareous sandstones, and shales, suggesting a shallow marine depositional environment. This formation is rich in marine fossils such as ammonites, brachiopods, bivalves, and corals, which help in precise age determination and correlation. Overlying the Jaisalmer Formation is the Baisakhi Formation, which is composed of sandstones and shales with occasional limestone bands. It represents a transition from