<img width="369" height="297" title="Image of limestone" alt="Image of limestone" src="iamges/naturalHistory/rocks/limestone.jpg" />
On the road from Cincinnati to Lake Erie, [limestone] is found to be the flooring of the Miami and Glaixe [Auglaize] Rivers.
A View of the Soil and Climate of the United States of America, C. F. Volney, 1803
Limestone is a fine- to medium-grained crystalline rock. It chiefly is composed of the mineral calcite. Ohio limestone sometimes contains the fossil remains of animals or plants that lived in the oceans from which the limestone was formed.
Limestone typically is formed by the precipitation of calcium carbonate, which is the chemical substance from which the mineral calcite is formed. The calcium carbonate may be dissolved in seawater, or it may have been accumulated by organisms that lived in oceans.
The process of forming limestone occurs in warm, clear, shallow seas. If a particular limestone is clean and free of small particles such as sand, then it was formed out and away from ocean shorelines, away from the area where rivers could carry particles of sand or clay.
Much of the limestone that is found in Ohio today occurs in the western half of the state. It was formed a long time ago during what is called the Early Paleozoic Era. This geologic period was between approximately 500 and 380 million years before the present time. Notable deposits also occur in the eastern part of the state. These are between 380 and 245 million years old. Limestone is an important industrial mineral in Ohio.<img width="175" height="131" title="Image of limestone" alt="Image of limestone" src="images/naturalHistory/rocks/limestoneinsert2.jpg" />
Builders used a variety of limestone known as "Columbus Limestone" for the exterior walls of the Ohio Statehouse. The building stone was taken from a quarry on the west banks of the Scioto River.
Every time a ton of steel is recycled, it means 2500 pounds of iron ore, 1000 pounds of coal, and 40 pounds of limestone will NOT have to be mined from the earth.
- Coogan, Allan H. Ohio’s Surface Rocks and Sediments; Chapter 3 in Fossils of Ohio, edited by Rodney M. Feldmann; Ohio Geological Survey, Bulletin 70, 1996.
- Pough, Frederick H. A Field Guide to Rocks and Minerals; Houghton Mifflin, Boston, MA; 1976.
- Sorrell, Charles A. Rocks and Minerals; Golden Press, New York, NY; 1973.
- Wolfe, Mark E., compiler 1997 Report on Ohio Mineral Industries; Ohio Division of Geological Survey; 1998.