The geology of the area in and near the City of Wabash, located in Wabash County along the upper Wabash River (Fig. 1), has had an important role in the development of modern concepts of Silurian sedimentation and reef growth in the southern Great Lakes area. The geologic significance of this area goes beyond an understanding of Silurian rocks in themselves, as Silurian reef studies have served as models in the development of fossil-reef and attendant sedimentation concepts throughout the geologic column.

One focal site is that of one of the best known fossil reefs in the world, The...