GUELPH FAUNA IN THE STATE OF NEW YORK 67 



The term Coelocaulus was introduced by Oehlert in 1888 for Devonic 

 species of these Murchisonias ; and Murchisonia logani has, on 

 the basis of Hall's original figure, been referred to that genus by Ulrich. 1 

 The name was however preoccupied by Hall for a genus of Bryozoa ; 

 but recognizing the usefulness of the distinction intended, we have sug- 

 gested the term here employed, Coelidium. Coelidium is pretty clearly 

 distinguished from forms referred to Hormotoma by the more depressed 

 whorls (when round), the less oblique suture and extended aperture and the 

 perforate axis. 



Coelidium macrospira, originally described from the Guelph of 

 Ontario, has also been recognized among the fossils of the Guelph beds of 

 Wisconsin. 



Coelidium cf. vitellia Billings 



Plate 7, fig. 9, 10 



Murchisonia v i t e 1 1 i a Billings, Paleozoic Fossils. 1865. i: 156, fig. 138 



Murchisonia vitellia Nicholson, Paleontology Prov. of Ontario. 1875. p. 3, 



fig. 6 



Murchisonia v i t e 1 1 i a Whiteaves. Paleozoic Fossils. 1895. 7.3, pt 2, p. 80 



In the material from Rochester is a single incrusted shell of a rather 

 large species of this genus with relatively short and stout spire presenting 

 an apical angle of 45 to 50. Through the incrustation of the surface the 

 whorls show a low carination, and the vertical section which reveals the 

 open axis of the shell also indicates the angularity of the whorls at the 

 position of the slit band. This specimen bears six volutions. It is a shorter 

 and stouter shell than C. macrospira, and, of the various species of 

 Murchisonia with Coelidium characters which have been described from 

 the Guelph fauna, this approaches most closely to Billings's species M 

 vitellia from Gait, both in the angle of the spire and the number and 

 form of the whorls. 



'Geol. Sur. Minnesota. Paleontology. 1897. v. 3, pt 2, p. 1019. 



