© 2019 Elsevier Ltd The Olmos Formation (upper Campanian) is located in the Sabinas Basin in northern Mexico. It represents a deltaic-fluvial system, and it is known by its abundance of fossil plants mainly represented by leaves and woods. In this contribution, we describe angiosperm fossil leaves, related to ?Violaceae. The new fossil genus has pinnate venation, with a major secondaries festooned semicraspedodromous, tertiary venation opposite percurrent, quaternary veins irregular reticulate, margin crenulated with tooth terminating in a glandular tissue, and fimbrial vein present. This mosaic of characteristics supports the creation of a new genus and species, Mascogophyllum elizondoa Centeno-González, Porras-Múzquiz et Estrada-Ruiz (?Violaceae). This record could be the oldest of the family; also, a new family is added to the very diverse fossil flora record that established during the Cretaceous in the northern of Mexico.