Transcription contributed by Martie Callihan 11 February 2005

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In briefly describing the geological features of the county, only the leading points can be noticed. The attempt will be made to treat the subject in such a manner that it can be understood by any intelligent reader, although unacquainted with the technicalities of geological science. Free use will be made of the information contained in the reports of the two Ohio geological surveys, and especially of Prof. Edward Orton's papers on the Southwestern Geological District in the report of the last geological survey. The line of junction between two geological formations passes through several counties in Southwestern Ohio, of which Warren is one. The physical features of the county are thus very similar to those of Preble, Montgomery, Miami, Clinton, Greene and Clark. Warren County shows better than any of the others the uppermost beds of the blue limestone formation, called the Lebanon beds.

The blue limestone strata are the floor of the county. Over these strata there are four or five outliers of the Cliff limestone, occupying in all not more than ten square miles of the area of the county. Over both blue and Cliff limestone formations are spread the deposits of the Drift period, consisting of superficial clays, sands, gravels and bowlders. The geological strata of the county, beginning with the lowest, are the blue limestone, called the Cincinnati group, the Clinton formation, the Niagara formation and the Drift. In a chart of geological history, the formations constituting the stratified rocks of the county belong to the Palaeozoic era, the blue limestone belonging to the Hudson River period, of the Lower Silurian age, and the Clinton and Niagara limestones belonging to the Niagara Period and the Upper Silurian age. The beds of drift belong to the Human era and Glacial epoch.

From the lowest exposed rocks in the county to the highest, there is a Tertical scale of about 500 feet divided among the three formations as follows:

Niagara Limestone, 50 feet; Clinton Limestone, 16 feet; Blue Limestone, 434 feet

The name blue limestone indicates the color of these strata of rocks. The bluish tinge of the rocks is due to the presence of an oxide of iron. Exposure to the weather frequently changes the color to a light gray or drab. The layers of this stone in Warren County range in thickness from three to eight inches. Between the layers of limestone are beds of shale, commonly called blue clay. Both the limestone and the blue clay contain numerous well-preserved fossils of ancient living forms inhabiting the seas, at the bottom of which these beds were formed.

The Clinton and Niagara formations have been popularly known as the Cliff limestone, and were so called in the first geological survey of Ohio. The valuable building stone known as Dayton stone, belongs to the Niagara formation. On the geological map of Warren County, four outliers of the Cliff limestone are marked. The largest of these includes a part of Clear Creek and Wayne Townships, and has its center nearly midway between Mount Holly and Franklin. The next in size is at Spring Hill, in Washington and Massie Townships. The other two are quite small, one being on a hill on the farm of William Morris, one mile east of Utica, and the other on the east side of the Little Miami, near Freeport. The last-named outlier embraces about three-fourths of an acre, and is about sixteen feet thick. Prof. Orton, perhaps without sufficient evidence to warrant the conclusion, regarded it as a gigantic bowlder which must have been transported from the highlands west of the river. His reason for the conclusion is that the outlier overlies drift material of clay and gravel, and is at least 125 feet below the elevation required at this point for the formation. Spring Hill is interesting from the fact that it is the most southern of the outliers of the Clinton limestone in Ohio.

The Niagara formation is found in Warren County over the largest of the four areas of the Clinton formation just referred to. Some valuable quarries of Dayton stone are here found. The formation is here at least fifty feet in thickness and the highest land in the county is believed to be found in this locality.

The Drift beds are spread over almost the entire county. They consist of clays, sands, gravels, bowlders [sic] and buried vegetable remains, all of which have been transported by glacial action or by glaciers and icebergs, a greater or less distance from the places of their origin. These beds vary much in depth, in the materials of which they are composed and in the order in which the

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Considerable quantities of clean sand and gravel are found in these beds. In many parts of the county gravel-banks are numerous, and, in connection with the gravel found along the streams, have furnished excellent materials, for the turnpikes which traverse the whole county in every direction.

Bowlders are scattered irregularly over the county as well as other portions, of the Miami country, and constitute an interesting feature of the surface geology. They are termed erratic rocks, hardheads or grayheads. They are universally recognized as of Northern origin. They are composed of rocks foreign, not only to the county, but to Ohio. All geologists agree that many of them were brought from the Lake Superior region and the Canadian highlands, and that far the greatest number have been brought from beyond the great lakes. Prof. J. S. Newberry, late Chief Geologist of Ohio, believes that these bowlders were deposited at a later date than the most recent stratified beds of drift, and that they were floated to their present resting-places by icebergs, just as icebergs are now known to transport great quantities of rocks, gravel and sand, sometimes in the case of a single iceberg, amounting to 100,000 tons. The largest bowlder in Southern Ohio yet described is found about three miles southeast of Lebanon, and has given the name to the Rock Schoolhouse. It measures, above ground, seventeen feet in length, thirteen feet in breadth and eight feet in height. As it is found to slope outward in all directions under ground, it is fair to suppose that at least one-half of it is buried. It weathers rapidly, and must have been formerly considerably larger. Estimating it to weigh 160 pounds to the cubic foot, the weight of the bowlder must be not less than 275 tons. The composition of this and most other large bowlders of the region, is gneiss, in which reddish feldspar is a large element. Not only the bowlders, but the gravels of the drift beds, are of Northern origin. Among the pebbles found in the drift gravel are representatives of all the formations found to the northward in Ohio, Blue limestone, Clinton, Niagara, Water lime, corniferous and black slate, and the granitic rocks found beyond the lakes.

Fossils of great beauty and variety are found in abundance throughout the county. Perhaps no locality in the world furnishes superior facilities for the study of the fossils of the upper beds of the Lower Silurian. They occur in such numbers and are so perfectly preserved that the most careless observers have their attention directed to them in the stones by the wayside and in the pavements of streets. They are oftimes so crowded as to constitute the chief substance of the rocks. Longstreth's Branch in Turtle Creek Township, which empties into the Little Miami opposite Freeport, has given several new fossils to science, among them two new crinoids, both discovered by J. Kelly O'Neall, Esq., and one of which bears his name—the Glyptocrinus O'Nealli. A fossil seaplant found near Waynesville, and now in the cabinet of Israel Harris, has been named Fucoides Harrisi,

The soil of a great part of the county is of foreign origin; that is, it has not been derived from the decomposition of the underlying strata of rocks and shale, but has been transported by the drift agencies from northern sources. As the underlying rocks are limestone and the gravels of the drift largely composed of the same kind of rock, the soil is calcareous and of wonderful fertility. It is, in fact, an extension of the famous Blue Grass Region of Kentucky, and its equal in fertility and beauty of scenery. As fine fields of blue grass are to be found in Southwestern Ohio as in Kentucky. In, the lower valleys of the

Most parts of the county have a fair, supply of good water. Spring Hill derives its supply from the Clinton limestone, with which it is capped The main water supply of the county, however, is derived from the drift beds, in which good water is generally obtained for wells at a depth of from fifteen to twenty-five feet The most noted string in the county is near Springboro, and has long been turned to account in running one or more mills. This spring, or, rather, series of springs, uniting in one current, has its origin in heavy beds of drift. Near Harveysburg, in a beautiful grove, is the collection of springs known as the "Fifty Springs." At Lebanon are two chalybeate and one sulphur spring. Where the blue limestone formations are not covered with drift beds, the water supply is inferior. The rainfall cannot penetrate the compact clays of this formation, and is consequently turned to the streams by surface drainage. There are comparatively few farms in the county upon which an adequate supply of water for domestic purposes and farm animals cannot be obtained, even in the dryest seasons, either from rivulets, springs or wells.