Detailed outcrop studies of the Cretaceous Ferron Sandstone reveal the spatial relationships between facies in a fluvial-deltaic system. Outcrop data include detailed and regional geological mapping, gamma ray transacts, and core plug transacts. These data are supplemented by laboratory measurement of plug porosity and mini-permeater measurement of plug permeability, petrographic analysis of plugs, {open_quotes}behind-the-outcrop{close_quotes} boreholes, detailed mini-permeameter measurements on these cores, and wireline logs. Prograding delta front clinoforms within -the seaward-stepping Kf-1 parasequence show a systematic decrease in permeability from the proximal delta front (k{sub avg} {approx} 20 md) to the distal delta front (k{sub avg} 1 00 md). Individual parasequences are up to a few 10s of meters thick, are amore » really extensive, and are often isolated from one another by nearly continuous mudstone and siltstone up to a meter thick. Multiphase flow simulations illustrate how lithofacies architecture and the juxtaposition of related lithofacies impact reservoir efficiency.« less