consists of small beds lying at an
angle to the main sedimentary layering (Fig. 7–17a).
Cross-bedding forms in many environments where wind
or water transports and deposits sediment. For example,
wind heaps sand into parallel ridges called dunes, and
flowing water forms similar features called sand waves.
Figure 7–17b shows that cross-beds are the layers formed
by sand grains tumbling down the steep downstream
face of a dune or sand wave. Cross-bedding is common
in sands deposited by wind, streams, ocean currents, and
waves on beaches.