96 CANADIAN FOSSILS. 



it shows an inclination to vary extremely "in the vertical dimensions 

 of the carapace, so that in the same hand specimen, some individuals 

 are ovate-oblong, and others narrow and pod-shaped. This habit of 

 variability of outline is not apparent in the Canadian Lejjerditia above 

 described. 



Other localities in Canada are mentioned by Sir W. E. Logan and 

 Mr. Murray for Entomostraca — probably X. Canadensis or allied forms, 

 namely : — 



Three miles above Lachine ; in the Trenton limestone ? * 



Indian Lorette near Qaebec ; in the Birdseye limestone ? t 



Three or four miles from Montreal, in a line a little west of north; 

 in the Birdseye limestone. | 



Sheik's Island, Cornwall,^ ; with Atrypa plena in the Chazy. 



Cornwall ; in the Trenton limestone ||. 



Lancaster ; in the Black River limestone^. 



Winchester ; in the Trenton limestone**. 



III. Leperditia Anna, Jones. 

 Plate XL Fig. 13. 



(Annals of Natural History, 3d series, vol. i. p. 247, plate ix. fig. 18.) 



Length i, breadth } inch. 



Small, convex ; ovate-oblong, somewhat narrower in front than 

 behind ; the ventral curve nearly uniform ; hinge-line straight ; dorsal 

 angles slightly truncate. Surface of valves most convex at the pos- 

 terior third; smooth, thickly punctate, each of the little shallow 

 circular pits having a minute central tubercle. Eye-spot distinct 

 and raised. 



Locality and Formation. — Several valves of this neatly-pitted 

 Leperditia are present in a small hand-specimen of a hard dark 

 colored concretionary limestone, under the zone of Atrypa plena, and 

 belonging to the Calciferous Sandrock, from immediately behind 

 the village of St. Ann'stt, at the confluence of the Ottawa and St. 

 Lawrence. This is probably the oldest known species of the genus. 



Collector. — Sir W. E. Logan. 



* Quarterly Journal Geological Society, vol. viii. p. 205. 

 . t Letter, Jan. IV, 1853. X Letter. 



§ Geol. Sur. Canada, Report, 1851-52, p. 70. 

 II Ibid. p. 70. IT Ibid, p. 71. ** Ibid. 72. 



tt Quart. Jour. Geol. Soc. loc. cit.; and Geol. Sur. Canada, Report, 1851-52, p. 16 



