In western Venezuela the tectonics, facies, and paleogeography of the Cretaceous, Paleocene, and Eocene are relatively well known. A study of the sandstones of these series affords a good case history to test some of the modern concepts in sandstone petrography such as tectonic control of sandstone properties and textural and mineralogical maturity. In this case sandstone mineralogy and mineralogical maturity are functions of source area petrography, weathering, and erosion. Textural maturity on the other hand is related to environments in the depositional basin. No fixed relation between tectofacies and depositional environments seems to be present. Consequently sandstone properties do not appear to depend to any great extent on the tectofacies in the basin. The observat ons suggest caution in applying to the field of sandstone genetics and sandstone classification general concepts as for example the idea of tectonic control of sandstone petrography.