Source : Webster's Revised Unabridged Dictionary (1913)

Shelfy \Shelf"y\, a.
   1. Abounding in shelves; full of dangerous shallows. ``A
      shelfy coast.'' --Dryden.

   2. Full of strata of rock. [Obs.]

            The tillable fields are in some places . . . so
            shelfy that the corn hath much ado to fasten its
            root.                                 --Carew.

Source : WordNet®

shelfy
     adj : full of submerged reefs or sandbanks or shoals; "reefy
           shallows"; "shoaly waters" [syn: {reefy}, {shelvy}, {shoaly}]