WARREN COUNTY. 383 



most division, viz., the Lebanon beds. Besides this, it contains from 125 

 to 150 feet of the upper beds of the middle division, or the Cincinnati 

 beds, proper. These strata have dipped from a height of 450 feet at Cin- 

 cinnati, to that of 275 feet at Lebanon, an average fall of about six feet 

 to the mile to the northward, a result which is, in the main, harmonious 

 with the general facts already established in regard to the dip of the 

 Blue Limestone beds. 



The Cincinnati rocks furnish the floor of Warren county, as of South- 

 ern Ohio generally. Indeed, they constitute almost the entire surface of 

 the county, the Cliff Limestone not occupying more than ten square miles 

 of its area. The accompanying map indicates the outliers of the Cliff 

 Limestone and also the boundaries of the main valleys of the county. 



No detailed description of the strata of the Blue Limestone of Warren 

 county is necessary. All the typical peculiarities of this division of 

 rocks are shown here. As a consequence, the county is abundantly sup- 

 plied with an excellent quality of building-stone, which can also be 

 burned into lime fit for coarse work and for agricultural purposes. Unex- 

 ampled displays of the strata, especially of the upper division, are fur- 

 nished by the many tributaries of the Little Miami, so that every foot 

 of the vertical ascent can be studied in hundreds of exposures. As a 

 consequence, the fossils of the system are here displayed in their greatest 

 perfection. They occur in such numbers and in such striking and well- 

 preserved forms, that they can not fail to attract the notice of even care- 

 less observers. It is hardly necessary to name particular localities in 

 this connection, when every branch, if followed back from the river to 

 its sources, reveals these beautiful forms in wonderful profusion. A sec- 

 tion exposed on the old Lebanon and Wilmington road, just after it 

 crosses the Little Miami River, in passing eastward, deserves mention, 

 however, because of its unusual extent. It shows in a very steep ascent, 

 about two hundred feet, mainly of the Lebanon beds, beginning with 

 that stratum of Orthis biforata, which is taken as the summit of the Cin- 

 cinnati section proper. This locality is one of the best known for the 

 occurrence of the interesting form Orthis retrorsa, Salter, which comes in 

 at forty to fifty feet above the Orthis biforata bed. It has no monopoly of 

 this fossil, however, as the shell occurs in every section between Morrow 

 and Caesar's Creek that exposes its particular stratum. This locality is 

 of special interest, also, because it yielded the typical specimen of a new 

 crinoid — the Heterocrinus juvenis of Hall. 



A very interesting section is furnished by Longstreth's Branch, oppo- 

 site Freeport, which deserves special notice, also, on account of having 

 given several new fossils to science, among them two crinoids — Glypto- 



