SUMMARY OF THE STRATIGRAPPIY. 39 



6. None of the larger divisions of the Carboniferous of the west are entirely 



unrepresented in Ohio. 



7. The transition is nevertheless so gradual that we have an instructive illus- 



tration of the evolution of one age from the preceding with neither 

 catastrophe nor annihilation. 



8. There is an opportunity to trace the geographical variations in a species 



as distributed over a great area, and to observe the evolution of new 

 types therefrom. 



9. The entire thickness of the AYaverly is not far from 700 feet, though the 



highest consecutive section measures only 670 feet. 



10. The Cuyahoga fauna bears an unmistakable resemblance to the so-called 



Sub-Carboniferous of Belgium, especially that of Etage I, the lime- 

 stone of Fornai. 



In the present state of our knowledge of the stratigraphy of Missouri it is 

 perhaps hazardous to attempt to parallelize Ohio and western horizons, but 

 if, as Professor Calvin states, the Chouteau and therefore also the Litho- 

 graphic limestone are faunally lower than the Kinderhook at Burlington, we 

 may easily regard the Cuyahoga shale as the eastern equivalent of the series 

 including these limestones, the shales included, and possibly also the shales 

 below extending to the deep-blue shales superposed upon the Black shale which 

 here, as elsewhere, affords a well-marked horizon.^ Professor Saffbrd offers 

 a hint which seems to open the way for extending the generalization into 

 Tennessee as Avell. 



Representative Sections. 



The following representative sections derived from the northern and 

 southern exposures in the state, respectively, may be offered in illustration 

 of the stratigraphical correlations suggested. The figures are all actual 

 measurements, there being no composition of different partial sections, and 

 are as nearly accurate as need be. 



*A small PM^iipsia, practically indistinguishable from our P. serraticaudata, h&s been received 

 from the lower Burlington beds of Louisiana, Mo. 



VI— Bull. Geol. Soc. Am., Vol. 2, 1890. 



