PLATE XV A— Continued. 



Fig. 15. The interior of a brachial valve. The cardinal process consists of two independent ajjophyses, 

 not coalesced with the crural plates, the latter being- depressed at their origin but considei-ably 

 elevated at their extremities. The visceral region is concave on either side of a bi-oad median 

 ridge and its surface radially stiiated ; IVom its anterior margin the surface of the valve is 

 abi'uptly and evenly deflected. X 5. 

 Fig. 16. Cardinal view of the same specimen ; showing the width of the area, the posterior face of the car- 

 dinal pi'ocess and the elevation of the crural plates. X 5. 

 These figures are from the original ppecimens of the species. 



"Point Levis; in the ujyper part nf the Limestone No. 2, Qtiebec group." (Billisg.s.) 



Genus ANOPLIA, gen. nov. 



(See Plate XX.) ■ 

 Page 309. 



Anoplia nucleata, Hall. 



Fig. 17. Cardinal view of an internal cast of the pedicle-valve, retaining the impiessions of the extremely 

 oblique dental lamellie and the short median septum ; also showing the indistinct outline of the 

 muscular area. X 3. 

 Fig. 18. The interior of the bi'achial valve which has a close similaiity to that of Chonetes. X 2. 

 Oriskany sandstone. Albany county, N. ¥. 

 See also the illustrations in Palseontology of New York, Volume III, plate 91, figs. 1 a-d. 



Genus LEPT^NISCA, Beecher. 



Pago 300. 



LEPTiENISOA CON CAVA, Hall. 



(See Plate XV, figs. 30, 31.) 



Fig. 19. The exterior of a pedicle-valve ; showing the contoui- and character of the surface. X 2. 



Fig. 20. The interior of a brachial valve, somewhat impei'fect about the mai-gins and cardinal pi-oce&s, 



but showing the spiral brachial ridges and the thin median septum. X 2. 

 Fig. 21. Cardinal view of an imperfect brachial valve preserving the charactei- of the cardinal process, 

 which is deeply quadi-ilobate. X 3. 

 Figures 20 and 21 are from specimens illustrated by Mr. Beecher. 

 Lowei" Helderberg group. Near Clarksville, N. Y. 



i Lept^nisca adnascens, sp. nov. 



i-i Irirniii 

 Fig. 22. A pedicle-valve attached by neai-ly its entire outei- surface to the interior of a valve of Orthis 

 oblata. The specimen shows the dental lamella and median ridge dividing the muscular area. 

 X 3. 

 Fig. 23. A specimen retaining both valves, attached to Orthis perelegans. X 4. 

 Lower Helderberg group. Near Clarksville, N. Y. 



LEPT.ai;NiscA tangens, sp. nov. 



Fig. 24. The exterioi' of a pedicle-valve with the umbo flattened from attachment, and showing the low 



median sinus. X 2. 

 Fig. 25. The intei'ior of the same specimen ; showing the cicatrix of attachment {x), the deltidiura and the 



dental lamellae X 2. 

 Fig. 26. The extei-ior of a pedicle-valve in which the rugose growth has obscured the median sinus. The 



deep umbonal depression has been caused by attachment to some bryozoan. X 3- 

 Figs. 27, 28. Opposite sides of a pedicle-valve attached to a twig of Tkematopoka. X 3. 

 Figs. 29, 30. Opposite sides of a similar valve which has been attached to a frond of Fenbstella. X 3. 



These last two specimens show the bilobate exteiior, the deltidium, teeth, strong dental lamellae 



produced about the musculai- area, and the short median septum. 

 Lower Helderberg group. Near Clarksville, N. Y. 



