Muscatatuck Group of Devonian Age Rocks at the Falls of the Ohio

September 08, 2016

Falls-of-the-Ohio (2)

September 2016 Viewer's Choice

Photographer: Dale Chadwick
Summary Author: Dale Chadwick

The photo above shows the Falls of the Ohio, on the Ohio River between Clarksville, Indiana and Louisville, Kentucky. The skyline of Louisville is in the background. When a dam and locks were built to move traffic past the falls, layers of the Muscatatuck Group of Devonian rocks were exposed. Two distinct layers of limestone with some dolomite can be seen. Both contain a variety of marine fossils. The lower layer (light colored rock with small ponds of water) was evidently a less turbulent environment, as many of the fossils appear to be in their original positions. The higher, darker and broken layer on the left side of the picture contains many more fossils, broken and mixed -- a death assemblage. The specimens in the lower strata were covered with a layer of fine mud and did not photograph well. Pictures of fossils in the upper strata include from left to right a snail (Turbinopsis sp.), a colonial rugose coral and several solitary horn corals. Photo taken on August 16, 2016.