628 STUART WELLER 



the correct generic reference of the species. It undoubtedly is 

 not an Athyris, but it may be allowed to remain in that genus 

 until more definite knowledge of its characters can be gained. 



14. Spirifer sp. undesc. This is a peculiar, elongate, narrow species, 

 whose shell is plicated throughout. It has been named S. 

 maplensis, and a description with illustrations will be published 

 elsewhere. 



15. Spirifer biplicatus Hall. This species is not uncommon in the 

 fauna, the individuals not differing essentially from Burlington 

 specimens. The species is remarkable because of its exceed- 

 ingly elongate hinge-line, produced in long mucronate extensions. 



16. Syringothyris extenuatus Hall. A single brachial valve, of 

 rather large size, is the only representative of this species in the 

 collection. It agrees perfectly with similar specimens from the 

 Chonopectus Sandstone at Burlington. 



17. Aviculopecten ? sp. undet. A single imperfect specimen of a 

 very large Aviculopecten-like shell is preserved in the English 

 River collection. When complete, its breadth must have been 

 ioo mm or more, but its state of preservation is such as will not 

 admit of definition. 



18. Pernopecten cooperensis Shum. Several more or less imperfect 

 specimens are present in the collection, which may be certainly 

 identified with this species. The species has not been certainly 

 recognized in the Chonopectus fauna at Burlington, but it occurs 

 rarely at Kinderhook. It is especially characteristic of the 

 Kinderhook faunas of central Missouri and of the higher Kinder- 

 hook faunas at Burlington. 



19. Leiopteria spinalata (Win.). A single imperfect specimen of 

 this species has been observed from English River. Its char- 

 acters are not well shown, but it appears to be identical with 

 the Burlington shells. 



20. Leiopteria sp. undesc. 



21. Pteronites whitei (Win.). A single small specimen from English 

 River seems to belong to this species. Its extreme length is only 

 i5 mm , but it agrees in all essential characters with the larger 

 shells from Burlington and Kinderhook, and may be safely 

 considered 'as an immature individual. 



