THE CINCINNATI GROUP IN WESTERN TENNESSEE, 



BETWEEN THE TENNESSEE RIVER AND 



THE CENTRAL BASIN. 



A. The subdivisions of the Cincinnati group in Ohio. 



B. The Cincinnati group in the Tennessee river valley. 



1 . The Saltillo limestone. 



2. The Warren limestone. 



3. The Richmond limestone. 



4. The Mannie shale. 



C. The Cincinnati group between the Tennessee river valley and the Central 



Basin. 



5. The Leipers creek limestone. 



6. The Swan creek limestone. 



D. Conclusions. 



A. THE SUBDIVISIONS OF THE CINCINNATI GROUP IN OHIO. 



In 1865 Meek and Worthen' proposed the name "Cincinnati 

 group" for that part of the Ordovician which is exposed in Ohio. 



In 1873 Professor Orton^ divided the Ordovician of Ohio 

 into three divisions. The middle division included all rocks 

 exposed within the boundaries of the city of Cincinnati ; its 

 inferior limit was at low water of the Ohio river, its upper bound- 

 ary was formed by the highest stratum found in the Cincinnati 

 hills. This middle division was called by Professor Orton the 

 Cincirmati beds proper. All rocks above the highest stratum 

 exposed in the Cincinnati hills and below the lowermost beds of 

 Silurian age (the Upper Silurian of the Ohio Survey and of most 

 authors) were included in the upper division. The strata that 

 form the summit of the Cincinnati hills are found also in the 

 immediate vicinity of Lebanon. The base of the upper division 

 is also well exposed here, and its fauna has been carefully studied 

 by local collectors. Therefore the name Lebaiwn beds was given 

 to the upper division, although the nearest outcrops of the top of 

 the Lebanon beds are about seven miles north of Lebanon, and 



"■ Philadelphia Acad. Nat. Sci., Proc, Vol. XVII, p. 155. 

 ''Ohio Geol. Siirv., Vol. I, pp. 370-73- 



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