This photo taken on U.S. 48 near Walnut Bottom, West Virginia, is an example of both anticlines and synclines in the same formation. Anticlines (the feature on the left half) are downward-curving (convex) folds in rock that resembles an arch. The central part, being the most exposed to erosion, display the oldest section of rock. Synclines (the feature in the center) are upward-curving (concave) folds in rock that resemble a trough. The central part contains the youngest section of rock.
Thanks to Barbara am Ende for sharing this photo with the USGS Science in Action Flickr Group!