57 



margin more or less elevated and compressed, nearly straight to a point a 

 little behind the mid-length ; then passing with a rounded or sub-ano;ular 

 curve into the anterior margin. Ventral margin gently convex, often 

 nearly straight or slightly sinuated a little in front of the middle ; some- 

 what abruptly curved up to the anterior angle, more broadly ascending 

 posteriorly. Anterior extremity most projecting at about the mid-height, 

 where it is narrowly rounded ; posterior margin broadly rounded, often 

 obliquely truncated in the upper half or two-thirds. 



Surface with obscure concentric rings of growth, from half to two lines 

 wide. These are also covered with very fme obscure concentric lines. 



Length of the largest specimen seen, eighteen lines- The proportions 

 vary greatly, as may be seen by the following measurements of three 

 specimens : 



Length. Height at urabones. Greatest height. 



No. 1. 14 lines. 5 lines. 10 lines. 



2. 15 " 8 " 11 " 



3. 14 " 6 " 12 " 



The form is also variable ; the posterior margin being either broadly 

 and nearly uniformly rounded or more or less distinctly angulated, usually 

 Si little below the middle. 



Locality and Formation- — Between Cape Gaspe and Cape Rosier ; 

 Gaspe limestone. Lower Helderberg. 



^CoUector — R. Bell. 



GASTEROPODA. 

 MuRCHisoNiA Hebe. (N. sp.) 



Fig. 28. 



Fig. 2S.—Murchiso7iia Hebe. A cast of the interior. 

 See also Plate 5, fig. G. 



DcscriiMon. — From three to four inches in length ; apical angle about 

 20° ; whorls, about ten in a specimen thr33 a.i l oiu-Iiilfinc hes in length 



