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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    longer tlian tlie posterior, which is regularly rounded. Front inai’gin rather acute. All the specimens are of casts without trace of hinge teeth, muscle scars, or surface markings. Largest s|)ecimen : Lengtli 19“’; height 10‘5““. Another: Length 17''; height 9*“. Locality.—Sloop Bay, Yalcour Island. The type is in the Yale University Museum. Ctenodonta parvidens sp. nov. Shell oval in outline, usually flattened, but specimens from the harder layers show considei-able convexity below the umbo, with regular slopes to the anterior, posterior, and ventral mar- gins. The cast shows the im])ression of numei’ous very fine teeth on the hinge, but the number can not be counted as the beak is always flattened down upon the impression of the hinge. One specimen exhil)its 5 teeth on tlie anterior portion of the hinge. Another shows 7. The surface is marked by very numerous flue concentric lines of growth. Locality.—In shales and limy clays at the Hog’s Back, Ottawa. Clldophorus ohscuriis sp. nov. Shell small, longer than high, not very convex. ■ Basal mar- gin nearly straight, anterior margin regularly curved, posterior end compressed, the margin acutely rounded. In front of the beak the cast shows a short clavicular impression, which extends about half the distance to the lower margin. Length 6 ; height 4“'. Locality.—Trilobite layers, Sloop Bay, Yalcour Island. The type is in the Yale collection. Cyrtodonta tranceps sp. nov. Shell roughly rectangular in outline, strongly convex at the umbo and along a ridge which i*uns diagonally across the shell to the lower side of the posterior margin. In front of this ridge there is usually a slight depression running from the umbo to the middle of the lower side. The posterior margin is regularly rounded, the lower side straight or slightly indented. The anterior end extends a short distance in front of the beak. The slo])e to the hinge is flat and rather steep. The slope to the front and base is gently convex and more gradual. The surface is mai’ked by numerous concentric lines. Locality.—Yalcour Island, New York. The type is iu the collection of the Carnegie Museum.