We examine a continuum theory for smectic liquid crystals which allows some variation in the smectic layer spacing as well as the director tilt. The theory can model configurations beyond the scope of a constant director tilt approach. Two applications of the continuum description are discussed. The first models equilibrium configurations of a planar smectic C cell, where a variation in layer spacing occurs due to homeotropic type ordering on the boundary plates. Secondly, we employ the theory to examine the bookshelf and chevron structures which can form as a liquid crystal is cooled into the smectic phases. (C) 2003 Elsevier B.V. All rights reserved.