The Collaborative International Dictionary of English v.0.48:

Shelve \Shelve\, v. i. [imp. & p. p. Shelved; p. pr. & vb. n.
   Shelving.] [Perhapss originally from the same source as
   shallow, but influenced by shelf a ledge, a platform.]
   To incline gradually; to be slopping; as, the bottom shelves
   from the shore.
   [1913 Webster]