THE GUELPH FOKMATIOIST OP CANADA. 547 



Mtthchisonia Boylei, Nicholson. Plate XXYI. fig. 1. 



Shell turreted, with a long conical spire. Apical angle 18°. Whorls 

 ten or eleven in number, increasing regularly in proceeding from the 

 apex to the base, flat, with a well-marked spiral band or angulation 

 just above the suture. Suture apparently canaliculated. Body- 

 whorl not ventricose. Base somewhat produced below, apparently 

 with a small umbilicus. Length of the only individual observed two 

 and a half inches, width of body-whorl eleven lines. 



This species is distinguished from M. turritiformis, Hall, M. Estella, 

 Billings, and M. longispira, Hall, by its more rapid rate of expansion. 

 It is further distinguished by its apparently canaliculated suture, and 

 the existence of an angular band a little above the suture, causing the 

 lower portion of each whorl to project considerably above the upper 

 portion of the whorl next below. Above the band the whorls are 

 quite flat. 



The above description is taken from a fine gutta-percha cast, which 

 exhibits all the essential characters except the mouth. The original 

 specimen was discovered by Mr. David Boyle, Head master of the 

 Public School of Elora,, Canada, and is now in the Museum of the 

 University of Toronto. 



Formation and Locality. Guelph Limestones ; Elora, Ontario. 



Mukchisokta Vitellia, Billings. Plate XXYI. fig. 6. 



M. Vitellia, Billings, Pala3ozoic fossils of Canada, p. 156, fig. 138. 



Shell with an elevated and conical spire of about four angular 

 volutions. Apical angle rather more than 50°. Body-whorl strongly 

 ventricose, and, in common with all the other whorls, furnished with 

 a broad and flat spiral band along the middle, giving rise to an obtuse 

 angulation. "Whorls convex below the band; and flat or slightly 

 concave above it, except the upper whorls, which there are some- 

 what convex. The band is slightly concave ; and the surface exhibits 

 fine striae, with indications of stronger rugae, which curve backwards 

 above the band and forwards below it. 



In the best-preserved specimen in my collection, the length of the 

 shell, when perfect, must have been somewhat over two inches, of 

 which the body-whorl occupies one inch. The width of the body- 

 whorl is an inch and a half. 



M. Vitellia is readily distinguished from the other MurcMsonioz of 

 the Guelph formation by the general form of the shell, the angular 

 volutions, the broad flat or slightly concave band, and the great size 

 of the body-whorl. The aperture is unknown ; but the base appears 

 to have been rounded, and a small umbilicus seems to have been 

 present. 



Formation and Locality. Guelph Limestones ; Elora, Ontario. 



Mukchisonia Heectnia, Billings. Plate XXYI. fig. 2. 



M. Hercynia, Billings, Palaeozoic Eossils, vol. i. p. 158, fig. 141. 



Shell conical or trochoid, with a nearly flat base. Apical angle 

 about 65°. Whorls five or six, gently rounded, with a moderately 



