  We prove in an abstract setting that standard (continuous) Galerkin finite
element approximations are the limit of interior penalty discontinuous Galerkin
approximations as the penalty parameter tends to infinity. We apply this result
to equations of non-negative characteristic form and the non-linear, time
dependent system of incompressible miscible displacement. Moreover, we
investigate varying the penalty parameter on only a subset of a triangulation
and the effects of local super-penalization on the stability of the method,
resulting in a partly continuous, partly discontinuous method in the limit. An
iterative automatic procedure is also proposed for the determination of the
continuous region of the domain without loss of stability of the method.
