20 Cincinnati Society of Natural History. 



present numerous exposures of all but the lowest beds of 

 the series. Fossils are exceedingly abundant at many 

 horizons, and they are as a rule very well preserved. The 

 soils of this region are to a large extent derived from the 

 decay of the bed-rocks, the limestones yielding a much 

 more fertile soil than the shales. Glacial and loess deposits 

 cover a considerable portion of the area, modifying the 

 character of the soil and often concealing the bed-rock. 



The present paper is a study of the rocks of the Cincin- 

 natian series in the vicinity of Cincinnati, and of the brachi- 

 opods of this series — a class of fossils more abundant and 

 better represented than any other, except the bryozoans. 

 The discussion of the rocks is based on the literature of the 

 Cincinnatian series and on field observations made by the 

 writer through a period of several years. In the work on 

 the brachiopods, the literature and all available specimens 

 in the Museum of the University of Cincinnati were studied. 

 The bibliography of each species is as nearly complete as 

 possible. In the treatment of the different species, the 

 original description (if available) is given except where some 

 later one was considered better. This is followed by a 

 discussion of the distinctive characters and notes on the 

 occurrence and abundance at Cincinnati. 



The paper was prepared in 1911 and 1912 in partial 

 fulfillment of the degree of Master of Arts in the Department 

 of Geology of the University of Cincinnati. It is a pleasure 

 to acknowledge to Professor J. Ernest Carman my apprecia- 

 tion of his many helpful suggestions during the progress 

 of the work. 



II. Stratigraphy 



A. Lithology of the Cincinnatian Series 



The rocks of the Cincinnatian series are made up of thin 

 beds of shale and limestone. The shale beds vary in thick- 

 ness from a few inches to several feet ; the limestone strata 

 from a fraction of an inch to eight or twelve inches. The 



