Ripple marks

from The Collaborative International Dictionary of English v.0.48
Ripple \Rip"ple\, n.
   1. The fretting or dimpling of the surface, as of running
      water; little curling waves.
      [1913 Webster]

   2. A little wave or undulation; a sound such as is made by
      little waves; as, a ripple of laughter.
      [1913 Webster]

   {Ripple grass}. (Bot.) See {Ribwort}.

   {Ripple marks}, a system of parallel ridges on sand, produced
      by wind, by the current of a steam, or by the agitation of
      wind waves; also (Geol.), a system of parallel ridges on
      the surface of a sandstone stratum.
      [1913 Webster]
    

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