IX. THE GASTROPODA OF THE CHAZY FORMATION. 



By Percy E. Raymond. 



Plates XLVI-LV. 



Introduction. 



The Gastropoda of the Chazy Limestone seem to have been among the 

 first Paleozoic fossils to attract the attention of naturalists in this coun- 

 try. As early as the year 1818 C. A. Lesueur described and figured 

 the most conspicuous of the gastropods of the Chazy under the name 

 Mac lurite magna. From 18 18 until 1842 no species of Chazy fossils 

 were described, but in the latter year Ebenezer Emmons named and 

 figured several fossils from his Calciferous and Chazy groups, at Chazy, 

 New York. Five of these, and all to which he gave specified names, 

 were gastropods. They were : Maclurea magna Lesueur, Maclurea 

 striata Emmons, Maclurea labiata Emmons, Bellerophon sulcatinus 

 Emmons, and Scalites angulatus Emmons. 



Since Lesueur's generic name Maclurite had the ending ite, Emmons 

 corrected the spelling to Maclurea, the name which has come into 

 general use. To be strictly accurate, however, we must return to 

 Lesueur's original name for the genus, adding a terminal " s." This 

 name is hardly more objectionable than Dalmatiites, Ceratites, Cyrto- 

 lites, Agoniatites, Trocholites, or a host of other similar generic names. 



In 1847 James Hall recognized fourteen species of gastropods in this 

 formation. He described as new : Metoptoma ? dubia, Raphistoma 

 staminea, Raphistoma planistria, and its variety parva, Pleurotomaria 

 biangulata, Pleurotomaria antiquata, Capulus auriformis, Murchisonia 

 abbreviata, and Bucania rotundata. He referred Maclurea striata 

 Emmons to the new genus Raphistoma, and placed Bellerophon sulca- 

 tinus Emmons as the first species under the genus Bucania. To one 

 fragmentary specimen referred by him to the genus Pleurotomaria a 

 specific name was not given. 



Of Hall's species Metoptoma? dubia is the same as Orbicula? 

 {Archinacella) deformata Hall. Raphistoma plajiistria and variety 

 parva are the same as Raphistoma sta?nineum Hall, and Pleuroto??iaria 

 biangulata is a Trochonema. Pleurotomaria antiquata is indeter- 



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