Lake Arkona

Summary of prehistoric beaches from the six glacial lakes that preceded the modern Lake Erie

From Spring Hill and Zion to the Ohio state line in southeastern Lenawee County, the three Arkona beaches are faint and hard to trace. The same character continues throughout Ohio and Pennsylvania and western New York.[3] Between Spring Hill and the Ohio state line the Arkona beaches do not show the characteristics normal to those in the Saginaw and Black River valleys. The beaches appear as ill-defined gravel or gravelly soil. In the first belt is the faintest, the second is slightly stronger, and the third is the strongest.[3]

The most peculiar characteristic of the gravel belts is their stiff clay. The soil of these gravel belts is very stiff and forms clods. They are continuous for miles, maintaining a constant level, and then merge into a single set of ridges in the Black River valley. Unlike most beaches of sand, the remains of the Arkona beaches are only the base structure, which are heavily impregnated with clay. Except for their consistent elevation, they would not have been identified as beach remnants.[3] The Arkona beaches have been heavily modified by wave actions and the emergence of Lake Whittlesey. Initially, Lake Whittlesey's waves began the process of washing the top portion of the Arkona beaches away. Then, the depth of the lake grew and water currents along the bottom of the lake moved the larger gravels up slope to become part of the Lake Whittlesey beaches. Then a period of deep quiet water allowed fine clays to leave suspension and be deposited among the remaining gravel.[3]

As far south as Lenox the three Arkona gravel belts are distinct. Beyond, there are a few intervals in which only two are discernible. Still farther southwest the first and second ridges draw closer together and the vertical interval between them diminishes until it is often difficult to distinguish the two. The three ridges are distinguishable some distance beyond Britton, where the upper two are of very nearly the same height.[3] The same occurrence of three beaches was noted in the Saginaw basin between Flushing and Cass City, but west of Flushing only two beaches appear. In the Saginaw basin the Arkona beaches were not submerged, but they were uplifted. The full strength of the Arkona beach ridges near Cass City and Croswell makes it clear that the ice barrier stood at least 25 miles north, enough distance to allow a heavy on shore surf.[3]