Ripple marks

In geology, ripple marks are sedimentary structures (i.e., bedforms of the lower flow regime) and indicate agitation by water (current or waves) or directly by wind.

Straight ripples generate cross-laminae that all dip in the same direction, and lie in the same plane.

These forms of ripples are constructed by unidirectional flow of the current.

All laminae formed under this type of ripple dip at an angle to the flow as well as downstream.

Catenary ripples generate cross-laminae that are curvy but have a unidirectional swoop.