Abstract: Pterosaur fossils are rare in the Morrison Formation, and most are poorly preserved. The Breakfast Bench Facies (BBF) at Como Bluff produces incomplete but uncrushed limbs. One proximal and two distal femora match a complete femur (BYU 17214) referred to Mesadactylus . Unexpectedly, both of the BBF distal femora possess a large intercondylar pneumatopore. BYU 17214 also possesses an intercondylar pneumatopore, but it is smaller than in the BBF femora. Distal femoral pnuematicity is previously recognized only in Cretaceous azhdarchoids and pteranodontids. A peculiar BBF jaw fragment shows strongly labiolingually compressed, incurved crowns with their upper half bent backwards; associated are anterior fangs. We suspect this specimen is a previously undiagnosed pterosaur. Additional BBF material documents a diverse pterosaur fauna including a humerus with a greatly expanded ectepicondyle possibly from a non-pterodactyloid monofenestratan.

Abstract We illustrate how sediment budgets can be used to understand the relationships between tectonics and sedimentation and to estimate the partitioning of sediment in shelf, slope, and basin-floor fan compartments within ancient shelf-margin strata. The studied Lewis-Fox Hills shelf margin represents the early Maastrichtian infill of the Laramide-type Washakie-Great Divide basin of southern Wyoming. The shelf margin shows an evolution in two stages. In Stage 1, the shelf margin is characterized by rising shelf-edge trajectory associated with increasing clinothem volumes, widening marine topsets, and increasing clinoform heights; a relatively large fraction of the sediment budget is stored on the shelf compartment through Stage 1. In Stage 2, the shelf-edge trajectory becomes more progradational and is associated with decreasing clinothem volumes, wide coastal-plain topsets, and stable to decreasing clinoform heights; a larger fraction of the sediment budget is stored within deep-water compartments. We interpret that the evolution from Stage 1 to Stage 2 is driven chiefly by tectonic uplift of the adjacent mountains and associated basin subsidence: increasing in Stage 1 and stable to possibly decreasing in Stage 2. Sediment budget calculations suggests that average sediment supply to the basin was 4-16 × 10 6 ton/y, yield was within 200-2000 ton/km 2 /y, and hinterland maximum relief was 1000-3000 m. Integration of sediment budget estimates within source-to-sink evolution represents a powerful tool to build improved tectono-stratigraphic models, and develop predictive models for sediment storage across shelf-margin compartments.

Abstract The Pennsylvanian-age Tensleep Formation in south-central Wyoming is comprised of repeated limestones, sandy limestones, and sandstones. Strata of these varied lithologic units are folded over Beer Mug Anticline and cut by numerous intersecting fractures. The anticline, with a near-vertical forelimb and backlimb dip up to 50 degrees, provides an ideal analog for fracture systems in tightly folded Paleozoic hydrocarbon reservoirs. Fracture type and degree of development vary systematically with lithology, structural position, and degree of folding. Fracturing is most intense towards the core of the anticline, which locally consists of folding. Fracturing is most intense towards the core of the anticline, which locally consists of brecciated, oil-stained rock with large-scale vuggy porosity. Most of these strata exhibit inherited (F0) fracture patterns that predate folding, as well as fold-related extension fractures that trend approximately normal (F1) and parallel (F2) to the axis of folding.