The fauna of the Chazy limestone / by Percy E. Raymond.

  • Raymond, Percy Edward, 1879-1952.
Date:
[1905]
Catalogue details

Licence: In copyright

Credit: The fauna of the Chazy limestone / by Percy E. Raymond. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Cyrtodonta soUtaria sp. nov. Shell rouirhly triangular, the beak a little behind the ante- rior end. Hinge line short. The anterior margin is narrow and rounded, tlie base long and straight, incurved at about 45° with the iiiiii^e. Posterior regnlarlv rounded. Shell only moderately convex, the slope to the ]’>osterior end gradual and to the tVont nearly flat. Leno'th 15''; lieiffht 12’5''. Surface marked by concen- trie lines of o;i-owtli. I^ocality.—Ledge in pasture near Tracy Brook, Chazy, Hew York. Tlie type is in the Yale collection. Whitella canadensis sp. nov. Shell small, convex, subrectangular in outline. A promi- nent ridge extends from the beak to the lower posterior corner. From this ridge the slope to the cardinal and posterior margins is abrupt, while there is little slope to the front until a point in front of the beak is reached, when the slope is suddenly deflected. The surface is marked by concentric undulations. Locality.—Aylmer sandstone, Aylmer, Quebec. Clionychia margmalis sp. nov. Both valves moderately convex, the umbones somewhat depressed, but increasing rapidly in height, the greatest thick- ness of the valves being at about one-third the distance from the beak to the lower margin. Hinge line short. The poste- rior margin is broadly rounded, the lower margin semi-circular. The front is almost straight. The greatest convexity is along a line parallel to the front. The posterior and lower slopes are gentle, but the front slope is abrupt, almost 90° with the plane of union of the valves. The surface is marked by very fine concentric striae. One specimen is 20“' long and 26‘5'“ high. Locality.—Chazy and Yalcour Island, Hew York. The type is in tlie Yale collection. Ambonycilia f curvata sp. nov. Shell large, both valves very strongly convex, especially along the region of the front and middle of the valves. Beaks small, incurved, directed a little forward. Anterior slope abrupt and overhanging. Posterior and bottom slopes rather steep. Posterior wing short. The posterior margin is almost straight. The anterior margin is regularly curved. The length and breadth are neaily equal. Am. Jour. Sci.—Fourth Series, Vol. XX, No. 119.—November, 1905. 26