  Recent developments in theories of non-Riemannian gravitational interactions
are outlined. The question of the motion of a fluid in the presence of torsion
and metric gradient fields is approached in terms of the divergence of the
Einstein tensor associated with a general connection. In the absence of matter
the variational equations associated with a broad class of actions involving
non-Riemannian fields give rise to an Einstein-Proca system associated with the
standard Levi-Civita connection.
