Figure 4. (1) Outcrop exposure of ridge-forming fluvial sand bodies (photograph looking to the southeast). Sand bodies appear to be regularly spaced and are typically 2–10 meters thick and each can extend laterally over a kilometer. Dip is to the south in this photograph; (2) Typical outcrop exposure of fluvial sandstone showing subtle bar clinoforms down and to the right; (3) Exposure of carbonate-bearing soil succession overlain by a thick fluvial sand-body. Here pedogenic carbonates form two hardpan layers (two rugose ledges beneath capping sandstone), Jacob’s staff is 1.5 meters tall; (4, 5) burrows in sandstone layers in the Turney Ranch Formation; scale bars equal 5 cm.
parting lineations are also common (Archibald, 1982; this study). Archibald (1982; 1987) identified a ‘mega-ripple’ sedimentary structure with amplitudes up to 0.5mand wavelength greater than 1m within the Turney Ranch Formation. We also observed
multiple examples of these sigmoidal, repetitive structures (sometimes with ripple cross laminations and dune stratification on the inclined foresets) that are up to 1.5m thick, but more commonly 1.0–1.3m thick (Fig. 4.3). Archibald (1982) attributes
