6l6 TRANS. ST. LOUIS ACAD. SCIENCE. 



to the Devonian facias of the Sedalia corals in the 12th Annual 

 Report Geol. Survey of Territories, p. 159. 



During our present studies of a series of Sedalia trilobites from 

 Mr. F. A. Sampson's cabinet, we have compared them with for- 

 eign and American species. Among these fossils there are sev- 

 eral specimens of Phillipsia Sampsoni which in general form 

 approach a species from the Rhinish Devonian described by the 

 Landbergh Bros., Rheinischen Scht. Syst., p. 30, pi. 3, fig. 3, as 

 Trigonaspis lavigata^ Goldf. This species has a similar pygi- 

 dium to that of Phillipsia Sampsoni from Sedalia ; but its gla- 

 bella has a more decided proetoid form ; it has also 10 segments 

 in the thorax. The figure given of Phillipsia Sampsoni in the 

 Trans. N. Y. Acad. Sci. vol. 7, p. 249, represents the glabella of 

 this species tapering too rapidly to the front ; its sides are paral- 

 lel and conform more closely to the type of the genus. 



These early species of Carboniferous ProetidcE are only con- 

 fined to the American rocks. The only Devonian genus extend- 

 ing up into English carboniferous rocks is a species of Cyphaspis 

 found at Yorkshire, lately described in the Quart. Journ. Geol. 

 Soc, vol. 46, 1890, p. 421. 



Although the Chouteau limestones have long been known and 

 studied, it is a matter of considerable doubt as to the exact hori- 

 zon to which they properly belong. The fossil crustaceae and 

 corals point to the Devonian ; we hope our friends in Sedalia 

 will clear up its classifications by extensive and systematic col- 

 lections of the organic remains. 



Amongst the American Carboniferous trilobites there are sev- 

 eral genera with ornamented and fimbricated pygidia. These 

 fossils have been classed under the genera Phcethonides and Dal- 

 manites{}). The first genus was described by Barrande in 1S46 

 under the name of PhcEton^ the author including under it both 

 proetoid and fimbricated pygidia. This term being preoccupied 

 in Natural History, Corda in 1S47 proposed for such species of 

 the Proetidce the name of Prinopeltis. Barrande placed all the 

 species described in his earlier work under Proetus in the Syst. 

 Sil. Boheme, vol. i, 1852. Angelin in 1854 revived the old name 

 oi Phceton^ changing it into Phcethonides ; this author follows 

 Barrande and includes Asaphns Stokesit, Murch., under the ge- 



