Weller — Kinderhook Faimal Studies. 41 



observed, and one of these differs from the above description 

 in the character of the revolving costae, which are all nearly 

 equal in size. Both specimens are imperfect and it is pos- 

 sible that they should be referred to some one of the species 

 of Bellerophon already described from about this horizon, but 

 which has never been illustrated. 



Bellerophon sp. 



This is a smooth, subglobular species with a narrow, incon- 

 spicuous peripheral band, and has much the aspect of B. sub- 

 laevis of the St. Louis Limestone fauna. It is represented 

 by several imperfect and distorted specimens none of which 

 are sufficiently well preserved to be described in detail or 

 illustrated. 



MOURLONIA NORTHVIEWENSIS n. Sp. 



PI. V. f. 13. 



Shell about 25 mm. in diameter, turbinate, umbilicate, 

 whorls angular on the periphery, sutures deeply impressed, 

 total number of whorls unknown. The peripheral band nar- 

 row, flat, and slightly elevated. Slopes of the shell, both 

 above and below the peripheral band, moderately convex and 

 in the last whorl it rounds over quite abruptly below into the 

 umbilicus. The whole surface covered with fine, subequal, 

 revolving lines, and by lines of growth which on the upper 

 side of the whorls are about equal in size to the revolving lines, 

 but below the peripheral band they are less distinct. The 

 lines of growth below and those above meet at the peripheral 

 band in an angle of about 120°. The aperture is notched, but 

 without a peripheral slit. 



Remarks. This species is one of the Pleurotomaridae and 

 apparently possesses all the essential characters of the genus 

 Mourlonia . 



Pleurotomaria ? sp. 



This species is represented by a single imperfect and much 

 distorted specimen, though enough of it is preserved to show 

 it to be distinct. The peripheral band is angular and the fine, 

 regular lines of growth above and below it meet upon it in an 

 obtuse angle. On the upper slope of the whorl, about half 



