English: A Flute cast, a sedimentary structure in which a river current scours a specific shape into the base of a bed. This view is from below, i.e., from an overlying sand body that filled in (the "cast") the scour. From the Book Cliffs near Helper, Utah. Pen for scale. Flute cast is seen as darker brown shape, broadening and tapering toward the upper right of the picture, which is the paleocurrent direction as well.