268 POTTSVILLE FAUNA OF OHIO 



Orthoceras n. sp. 



Description. A small, gradually tapering Orthoceras from the 

 Sharon ore represents in all probability a new species, but the material 

 at hand is too poor for descriptive purposes. The siphuncle is con- 

 spicuously eccentric, and the septa strongly convex, being situated 

 from each other about one-fourth of their diameter. 



Horizon and locality. Sharon ore: Scioto County, Lick Run, 

 Locality 2, c. 



Orthoceras n. sp. 



Description. Several crushed specimens of a large Orthoceras 

 from the Lowellville and Lower Mercer members apparently belong to 

 the same species which is undescribed. The material at hand, how- 

 ever, is too poor and fragmentary for description and figuring. The 

 form appears to be gradually tapering, but other characters, such as 

 the position of the siphuncle an.d the ratio of ^ the height of the chambers 

 to their diameter cannot be determined. The species can be most 

 readily compared with 0. fanslerensis Keyes and 0. colletti Miller, but 

 they can be distinguished from the Ohio form by the greater height of 

 the chambers. 



Horizon and locality. Lowellville member ?: Muskingum County, 

 Holbein, Locality 20, r. Lower Mercer: Mahoning County, Little Mill 

 Creek, r. 



Genus Pseudorthoceras Girty 

 Pseudorthoceras knoxense (McChesney) 



1860 Orthoceras knoxensis. McChesney, Desc. New Spec. Foss., p. 69. 



(Date of imprint, 1859.) 



Ccal Measures: Knox County, Missouri. 

 1860 Orthoceras cribrosum. Geinitz, Die Carb. und Dyas in Nebr., p. 4, Tab. 1, Fig. 5,. 



Dyas: Nebraska City, Nebraska. 

 Pseudorthoceras knoxense. Girty, U. S. Geol. Surv., Bull. 544, p. 227, PL XXVII, 



Figs. 1-6. 



Wewoka formation: Oklahoma. 

 Also most or all of the citations, included under Orthoceras rushense, should be included 



under Pseudorthoceras knoxense. 



m 



Description. Pseudorthoceras knoxense is common in the marine 

 limestones of the Potts ville formation, but has not been found below 

 the Lowellville member. Although small, representatives vary con- 

 siderably in size; the form is gradually tapering and the siphuncle is 

 central or subcentral in position. The septa a.re moderately convex 

 with about three equaling the diameter of the shell at any point. The 



