118 PAL^OXTOLOGY OF OHIO. 



of the volution, and sub-angular at the junction of the uj^per and lower 

 surfaces of the outer lip. 



Surface of the shell marked on the upper part of the volutions by a 

 series of raised, revolving lines of varying strength," and crossed by 

 equally strong, concentric lines, which are directed obliquely backwards 

 from the suture to the periphery, where they are more abruptly bent 

 back to the center of the carina, below which they are as abruptly 

 directed forward, indicating a moderately deSp but narrow notch in this 

 part of the lip of the aperture. On the lower side of the volution the 

 concentric striae can be traced for a short distance, below which the shell 

 is imperfect in both individuals examined. No evidence of revolving 

 lines below the central band has been seen, and the probability is that 

 none have existed on this portion of the shell. 



The species is very closely related to P. Hebe, Hall, 15th Rept. State 

 Cab., pi. 5, fig. 8, and also to P. sulcomarginata, Conr., figured on the same 

 plate, and is, so far as we are aware, the only species of this type of the 

 genus recognized in this country from a formation below the Upper Held- 

 erberg group. It differs from both of the above named species in the 

 greater elevation of the spire. 



Formation and locality: In the iron ores of the Clinton group, Clinton county, Ohio. 

 Collection of XJ. P. James, Esq. 



CEPHALOPODA. 



Orthoceras Jamesi (n. sp.). 



Plate 5, fig. 13. 



Shell small, and very moderately expanding with increased growth, 

 the fragment used in description being only about five-eighths of an inch 

 in length, with a diameter of five-sixteenths of an inch at the upper 

 end, and a little less than a quarter of an inch at the lower extremity of 

 the fragment, giving about a twelfth of an inch increase in diameter in 

 the length of the specimen. Transverse section circular, not compressed. 

 Septa very moderately and evenly concave, apparently regularly dis- 

 posed, about three and half of the chambers occupying a space equal to 

 the diameter of the shell at the top of those measured. Siphuncle not 

 clearly determined. 



Surface of the shell rather coarsely, but deeply and beautifully, cancel- 

 lated by sharp longitudinal and transverse ridges, the former nearly reg- 



