The Collaborative International Dictionary of English v.0.48:

Conculcate \Con*cul"cate\, v. t. [imp. & p. p. Concultated; p.
   pr. & vb. n. Conculcating.] [L. conculcatus, p. p. of
   conculcare to conculcate fr. calx heel.]
   To tread or trample under foot. [Obs.] --Bp. Montagu --
   Con`cul*ca"tion, n. [Obs.]
   [1913 Webster]