Fossils of the Calcifeious Sandrock. 349 



LlNGULA MANTELLI. (N. S.) 



Fig. 1— e,f. 



Description. — Elongate-oval, sides sub-parallel, gently convex 

 for rather more than half the length, then gradually curving to 

 the beak, front moderately rounded. Surface, when partially ex- 

 foliated, covered with longitudinal radiating striae. Length four 

 or five lines, width rather more than half the length. Both valves 

 are very convex, and do not appear to have the plane surfaces 

 of L. Lyelli. 



Although the form is somewhat like that of the young speci- 

 mens of L. Lyelli, yet it is clear that this is a distinct species. 

 It occurs in a different locality, and although very abundant, 

 none of the specimens are more than six lines in length, the 

 average size being from four to five lines. It is a smaller, and 

 also proportionally more convex species than L. Lyelli. 



None of the specimens that I have seen have the shell well 

 preserved, and I am unable, therefore, to say what the character 

 of the surface may be when perfect. 



Dedicated to the late Dr. Man tell, author of the Medals of 

 Creation, <fcc. 



Locality and formation. — Near the Village of St. Eustache 

 Calciferous sandrock. 



Collectors. — A Murray, J. Richardson. 



Orthisina grand^eva. (N. s.) 

 Fig. 1 — sr, h, i. 



Description. — Ventral valve depressed pyramidal, nearly semi- 

 circular, area large, inclined backwards at an angle of about 125° ; 

 foramen closed, all except a small space at base, the apex per- 

 forated ; surface with fine radiating striae, of which there are 

 four or five in one line at the margin ; width of the only specimen 

 seen, at hinge line, seven lines; length, from hinge line to front 

 three lines and a half; length from beak to front, six lines ; height 

 of area, two lines. Dorsal valve unknown. 



It is not certain that this species belongs to the genus 

 Orthisina ; but, as the foramen is nearly closed, it appears more 

 closely allied to that genus than to Orthis. A single, but very 

 perfect valve is all that has been collected. 



There are, besides the above, in the White Limestone at the 

 Mingan Islands, numerous casts of a species of Orthis or Orthi' 

 sina, which have the same form as 0. grandceva, and appear to 



