50 Trans. Acad. Sci. of St. Louis. 



York Hamilton and Chemung faunas, and the abundance of 

 the two species of Palaeontilo may be considered as Devonian 

 elements in the fauna. It is not surprising, however, to find 

 such an element in a fauna contained in strata lying almost at 

 the base of the Carboniferous. 



Aside from the twenty-four species already considered, the 

 following eight si)ecies described here for the first time, 

 deserve consideration : — 



Ambocoelia parva. Promacrus wehsttrensis. 



Crenipeclen laevis. Edmondia missouriensis . 



Modiomorpha northviewensis. Mourlonia northviewensis. 



Cardio/ms erecta. Platyschisma missouriensis. 



The genera are mostly those occurring in the Kinderhook 

 faunas elsewhere. Ambocoelia parva is allied to A. minuta 

 of the Kinderhook, and also to the Devonian species A. um- 

 honata. Promacrus websterensis is most closely allied to P. 

 missouriensis from the Kinderhook in Pike County, Missouri, 

 but it is also less closely allied to P. andrewsi which was de- 

 scribed from the Waverly group in Ohio. The genus Platy- 

 schisma is here recognized for the first time in America. In 

 Europe it is represented by several species in the Carbonifer- 

 ous limestone. To the genus Mourlonia^ several species, both 

 Devonian and Carboniferous, usually placed in Pleurotomaria, 

 will probably have to be added. 



EXPLANATION OF ILLUSTRATIONS. 



Plates II.-VI. 

 (all of the figures are of natural size.) 



Plate II. — 1, Promacrits viissouriensis Swall. A copy of Meek's figure of 

 this species, introduced here for comparison with P. icebsterensis. — 2, Pro- 

 macrus tcebsterensis n. sp. Lateral view of one of the type specimens. 



Plate III. — 1, Promacrus icebsterensis n. sp. One of the type specimens 

 showing the long groove near the dorsal margin posterior to the beak. — 2, 

 Promacrits cuneatus Hall. Lateral view of a nearly perfect left valve. — 

 3-4, Cardiopsis^ erectus n. sp. View of a perfect right valve and a profile of 

 the same in outline. — 5-6, Cardiopsis radiata M. & W. View of a perfect 

 right valve and a profile of the same in outline. — 7, Sanguinolites webster- 

 ensis n. sp. Lateral view of a nearly perfect right valve. — 8, Macrodon sp. 

 Lateral view of a nearly perfect right valve. — 9, Elymella missouriensis 



