Tlie Cinciunatian Series and its Brachiopods. 19 



III. Geologic and Physiographic History 



A. Paleozoic Era 



1. Cinciunatian epoch 



Eden stage 

 Maysville stage 

 Richmond stage 



2. Silurian period 



B. Post-Paleozoic Time , 



IV. History of the Nomenclature 



Correlation Table 



V. Bibliography 



PART II 



I. General Discussions of the Brachiopods 



A. \'alue as Horizon Markers 



B. Progressive Evolution 



C. Table of Range and Relative Abundance of Thirty 



Species 



D. Complete List of Brachiopods reported from the 



Cinciunatian Series of the Vicinity of Cincinnati, 

 Ohio 



II. Description of Species 



PART I 



I. Introduction 



The region about Cincinnati is underlain by a series of 

 alternating shales and limestones. This series, to which 

 the name Cinciunatian has been given, is of Upper Ordo- 

 vician age. The city of Cincinnati lies to the north of the 

 center of a low dome. To the east, north, and west of it, 

 are younger rocks; to the south of it, are older rocks. The 

 quarries about Cincinnati, the steep valley-sides of the 

 Ohio River, and especially the beds of the smaller valleys 



