The Collaborative International Dictionary of English v.0.48:

Superficiary \Su`per*fi"ci*a*ry\, n. (Rom. Law)
   One to whom a right of surface occupation is granted; one who
   pays quitrent for a house built upon another man's ground.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Superficiary \Su`per*fi"ci*a*ry\, a.
   1. Of or pertaining to the superficies, or surface;
      superficial.
      [1913 Webster]

   2. (Rom. Law) Situated or built on another man's land, as a
      house.
      [1913 Webster]