  Geometric Singular Perturbation Theory (GSPT) and Conley Index Theory are two
powerful techniques to analyze dynamical systems. Conley already realized that
using his index is easier for singular perturbation problems. In this paper, we
will revisit Conley's results and prove that the GSPT technique of Fenichel
Normal Form can be used to simplify the application of Conley index techniques
even further. We also hope that our results provide a better bridge between the
different fields. Furthermore we show how to interpret Conley's conditions in
terms of averaging. The result are illustrated by the two-dimensional van der
Pol equation and by a three-dimensional Morris-Lecar model.
