Fig. 15. 
Fig. 16. 
Fig. 17. 
Fig. IS. 
Fig. 19. 
Fig. 20. 
Fig. 21. 
Fig. 22. 
Fig. 23. 
Fig. 24. 
Fig. 25. 
Fig. 26. 
Figs. 27, 
Figs. 29, 
PLATE XV a— Continued. 
The interior of a brachial valve. The cardinal process consists of two independent apophyses', 
not coalesced with the crural plates, the latter being depressed at their origin but considerably 
elevated at their extremities. The visceral region is concave on either side of a broad median 
ridge and its surface radially striated; from its anterior margin the surface of the valve is 
abruptly and evenly deflected. X 5. 
Cardinal view of the same specimen ; showing the width of the area, the posterior face of the car¬ 
dinal process and the elevation of the crural plates. X 5. 
These figures are from the original specimens of the species. 
“Point Levis; in the upper part of the Limestone No.'2, Quebec group” (Billings.) 
Genus ANOPLIA, gen. nov. 
(See Plate XX.) 
Page 309. 
Anoplia nucleata, Hall. 
Cardinal view of an internal cast of the pedicle-valve, retaining the impressions of the extremely 
oblique dental lamellae and the short median septum ; also showing the indistinct outline of the 
, muscular area. X 3. 
The interior of the brachial valve which has a close similarity to that of Chonetes. X 2. 
Oriskany sandstone. Albany county, N. Y. 
See also the illustrations in Palaeontology of New York, Volume III, plate 91, figs. 1 a-d. 
Genus LEPT.ZENISCA, Beecher. 
Page 300. 
Lept^inisca concava, Hall. 
(See Plate XV, figs. 30, 31.) 
The exterior of a pedicle-valve ; showing the contour and character of the surface. X 2. 
The interior of a brachial valve, somewhat imperfect about the margins and cardinal process, 
but showing the spiral brachial ridges and the thin median septum. X 2. 
Cardinal view of an imperfect brachial valve preserving the character of the cardinal process, 
which is deeply quadrilobate. X 3. 
Figures 20 and 21 are from specimens illustrated by Mr. Beecher. 
Lower Helderberg group. Near Clarksville, N. Y. 
LePTASNISCA ADNASCENS, Sp. 110V. 
A pedicle-valve attached by nearly its entire outer surface to the interior of a valve of Orthis 
oblata. The specimen shows the dental lamellae and median ridge dividing the muscular area. 
X 3. 
A specimen retaining both valves, attached to Orthis perelegans. X 4. 
Lower Helderberg group. Near Clarksville, N. Y. 
Leptaenisca tangens, sp. 110V. 
The exterior of a pedicle-valve with the umbo flattened from attachment, and showing the low 
median sinus. X 2. 
The interior of the same specimen ; showing the cicatrix of attachment ( x ), the deltidium and the 
dental lamellae X 2. 
The exterior 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. 
28. Opposite sides of a pedicle-valve attached to a twig of Trematopora. X 3. 
30. Opposite sides of a similar valve which has been attached to a frond of Fenestella. X 3. 
These last two specimens show the bilobate exterior, the deltidium, teeth, strong dental lamellae 
produced about the muscular area, and the short median septum. 
Lower Helderberg group. Near Clarksville, N. Y. 
