414 Procccdinys of the Ohio State Acadciiiy of Science. 



width of the vohition from the dorsal [ventral?] border. In- 

 ternal features of the shell not known. 



"A single individual only of the species has been observed. 

 and is altogether too imperfect to reveal all the features. It 

 consists of the non-septate portion of the shell, in the condition 

 of an internal cast, with the impression of one side of the entire 

 shell; but gives no indications of the septa themselves. The 

 only features indicating its cephalopodous nature, upon which 

 one can rely, are its symmetrical form and the evidence of a 

 similar ornamentation on the opposite sides ; otherwise it might 

 have been supposed to represent a form of Euoinphalus [Whit- 

 field, 1895]." 



Horizon and locality. — IMaxville limestone. 

 Upper zone: Mouth of Buckeye Fork (?), Fultonham ; Be- 

 low Thompson R^^sidence ( ?), White Cottage. 

 Lower zone: Cut Xo. 4. Alt. I'errv-I'ultonham. 



ORTHOCERAS RANDOLPHENSE-Worthen. 



Is'lil. Orthoceras aiuinlo-costatiivi. Meek and W'orthen, Proc. Acad. 

 Nat. Sci. Phil., p. 147, ( Xot O. anmiJato-costatum Boll, 1857). 

 Chester limestone: Chester, Illinois. 

 180i). Orthoceras aiinulato-costaiuiii. Meek and W'orthen, Geol. Siirv. 

 111., Vol. II, p. :^04, pi. -24, figs. 3a, h. 

 Chester group: Chester, Illinois. 

 1882. Orthoceras Randolphensis. W'orthen, 111. State Mus. Xat. Hist., 

 Bull. Xo. 1, p. 38. 

 Chester group. 

 1884. Orthoceras Kar.dolj^ticnsis ? W'alcott, U. S. Gcol. Surv., Mon. VIII, 

 p. -260, pi. If^, tig. 17. 

 Lower Carboniferous: Eureka District, Xevada. 



Description. — "Shell attaining a medituu size, and having 

 the form of an elongated, moderately compressed cone, the sides 

 of which converge towards the apex at an angle of about 14°. 

 Section elliptical, the greater transverse diameter being to the 

 smaller as 100 to 80. Surface ornamente:l with slightly oblique, 

 annular costas, which are less than the depressions between, and 

 rather sharply elevated on the smaller half of the shell, but 



