The Silurian reefs near Wabash, Indiana
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 Wabash Reef, which is exposed on either side of the Wabash Railroad cut that extends more than 1, 000 ft (300 m) northeastward from the end of East Market Street and immediately northeast of the site of the former Big Four Railroad Station in Wabash (SE¼SE¼Sec.11, T.27N., R.6E., Wabash 7½-minute Quadrangle; Figure 1). Generations of geologists on scores of field trips have been inspired by this reef exposure. Noted leaders in the developing study of Silurian reefs who made oft-cited observations here, not all of them correct, include E. M. Kindle, Edgar R. Cumings, Robert R. Shrock, Marius LeCompte, and Heinz A. Lowenstam.
The exposure is on the property of the Wabash Railroad, a busy rail line. Permission generally is not required, but a local employee of the railroad usually inquires the business of a fieldtrip group on the site and allows the group to continue its