A new formulation of simple D=4 supergravity in terms of the geometry of
superspace is presented. The formulation is derived from the gauge theory of
the inhomogeneous orthosymplectic group IOSp(3,1|4) on a (4,4)-dimensional base
supermanifold by imposing constraints and taking a limit. Both the constraints
and the limiting procedure have a clear {\it a priori} physical motivation,
arising from the relationship between IOSp(3,1|4) and the super Poincar\'{e}
group. The construction has similarities with the space-time formulation of
Newtonian gravity.Comment: 17 pages. Expanded version. To appear in Class. Quantum Gra