Age of flu Cincinnati Anticlinal. — Foerste. L05 
Clinton period this similarity is very striking-. It is observed in 
Guelph. Lower and Upper Helderberg periods. Even as late as 
Carboniferous times it would attract immediate attention if the 
anticlinal region be supposed to form a barrier. Tims the shales 
at the base of the Lower Coal Measures near Flint Ridge, at the 
eastern line of Licking county, Ohio, are full of marine fossils. 
The labors of Prof. C. L. Herrick have shown a striking identity 
between the mass of these fossils and those characteristic of the 
Coal Measures of Illinois, on the other side of the anticlinal. 
The bryozoa emphasize those observations, only one or two not 
being represented by forms in the Coal Measures of Illinois. Mr. 
F. 0. Ulrich in a locality at the same horizon near Seville. 
Illinois, has discovered a fauna so closely related to the bryozoa 
of Flint Ridge that if he had chosen to publish his discoveries 
first, it would have been scarcely possible to give good specific 
distinctions for the Ohio forms. Considering the great variability 
usually shown by bryozoa. this decided similarity or identity must 
be considered striking, even if a barrier such as that which would 
be formed by the anticlinal axis, he not supposed to exist. This 
similarity, however, must appear almost incredible, with the anti- 
clinal actually in existence. 
The most valuable information in regard to the structure of 
the Cincinnati anticlinal is that accumulated by Prof. Edward 
Orton, and published by him in 18SS in volume vi of the Ohio 
( Je< (logical Survey. 
By means of numerous records of wells bored during the late 
.oil and gas excitement in Ohio, Prof. Orton was enabled to con- 
struct numerous sections of Ohio strata, with varying degrees of 
reliability, but all sufficiently accurate to mid considerably to our 
knowledge of the geographical distribution of certain Paleozoic 
strata in the state. From these sections he constructed what 
might be called a contour map, with 250 feet intervals, of the 
Trenton as it would look at the present day if all superposed 
strata were removed. A glance at the geological map of Ohio, 
published by Prof. Newberry in 1879, would indicate an intimate 
correlation between the topograph}* of this Trenton land and the 
present outcrops of Paleozoic strata in the state. An extension 
of this comparison to the immediately adjacent regions of Indiana 
9 
