The Collaborative International Dictionary of English v.0.48:

Scarn \Scarn\, n. [Icel. skarn; akin to AS. scearn. Cf.
   Shearn.]
   Dung. [Obs. or Prov. Eng.] --Ray.
   [1913 Webster]

   Scarn bee (Zool.), a dung beetle.
      [1913 Webster]