Clark County, Ohio

History and Genealogy



Geological Formations


From 20th Century History of Springfield and Clark County, Ohio by Hon. William A. Rockel
Chicago: Biographical Publishing Co., 1908


In a work of this character only a cursory view of the geological formation of the county could properly be given.

According to the geological map of Ohio, the dividing course of the lower and upper silurian rock are wtihin the bounds of this county, the entire bed rock of Ohio being Trenton limestone, which is the first in formation in the lower silurian period. This rock takes its name from a picturesque and well-known locality in Trenton Township, Oneida County, New York. It has generally been recorded in Ohio as being found at a depth of from one to two thousand feet.

The Utica Shales ar ethe second in formation after the Trenton limestone and Professor Orton says, "In the wells of Springfield, Urbana and Piqua it is found in undiminished thickness, but in some more calcareous in composition."

As to what may properly constitute the geological scale applicable to Ohio, the following is taken from a work of Prof. Orton:

"A brief review of the scale and structure of the State will here be given, but before it is entered upon, a few fundamental facts pertaining to the subject will be stated.

"1. So far as its exposed rock series is concerned, Ohio is built throughout its whole extent of stratified deposits or, in other words, of beds of clay, sand and limestone, in all their various graduations, that were deposited or that grew in water. There are in the Ohio series no igneous nor metamorphic rocks whatever; that is, no rocks that have assumed their present form and condition from a molten state or that, subsequent to their original formation, have been transformed by heat. The only qualification which this statement needs pertains to the beds of drift by which a large portion of the State is covered. These drift beds contain boulders in large amount, derived from the igneous and metamorphic rocks that are found around the shores of Lake Superior and Huron, but these boulders are recognized by all, even by the least observant, as foreign ot the Ohio scale. Tehy are familiarly known as 'lost rocks' or 'erratics.'

"If we should descend deep enough below the surface we should exhaust these stratified deposts and come to the granite foundations of the continent which constitute the surface rocks in parts of Canada, New England and the West, but the drill has never yet hewed its way down to these firm and massive beds within our boundaries.

"The rocks that constitute the present surface in Ohio were all formed in water, and none of them have been modified and masked by the action of high temperatures. They remain in substantially the same condition as that in which they were formed.

"2. With the exception of the coal seams and a few beds associated with them, and of the drift deposits, all the formations of Ohio grew in the sea. Ther are no lake or river deposits among them, but by countless and infallible signs they testify to a marine origin. The remnants of life which they contain, often is the greatest abundance, are decisive as to this point.

"3. The sea in which or around which they grew was the former extension of the Gulf of Mexico. when the rocks of Ohio were in process of fomration, the warm waters and genial climate of the Gulf extended without interruption to the borders of the great lakes. All of these rocks had their origin under such conditions.

"4. The rocks of Ohio constitute an orderly series. They occur in widespread sheets, the lowermost of which are coextensive with the limits of the State. As we ascend in the scale the strata constantly occupy smaller areas, but the last series of deposits, viz., those of the Carboniferous period, are still found ot cover at least one-fourth of the entire area of the State. Some of these formations can be followed into and across adjacent States, in apparently unbroken continuity.

"The edges of the successive deposits in the Ohio series are exposed in innumerable natural sections, so that their true order can generally be determined with certainty and ease.

"For the accumulation and growth of this great series of deposits vast periods of time were required. Many millions of years must be reckoned in any rational explanation of their origin and history. All of the stages of this history have practically unlimited amounts of past time upon which to draw. They have all gone forward on so large a scale, sof ar as time is concerned, that the few thousand years of human history would not make an appreciable factor in any of them. In other words, five thousand years or ten thousand years make too small a period to be counted in the formation of coal, for example, or in the accumulation of petroleum, or in the shaping of the surface of the state throught he agencies or erosion."














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