Hall, James, 1811-1898 / Geological survey of Wisconsin, 1859-1863. Palaeontology. Part third
Plate XXV, pp. [unnumbered]-Pl. 25 PDF (1.7 MB)
PLATE XXV. OBOLUS CONRADI, HALL. Page 375. FIG. 1. Interior of a ventral valve, made from a cast in the natural mould. " 2. Interior of a smaller ventral valve, obtained by the same process as fig. 1. The dotted lines show the extent of the cavities beneath the transverse plate. 3. Interior of a dorsal valve, taken from a gutta-percha cast in the natural mould. The figures 2 and 3 are from the same casts as those figured on plate 13. SPIRIFERA PLICATELLA, var. RADIATA, SOW. Page 878. FIG. 4. Dorsal view of a large cast, showing the cavities left by the removal of the dental lamelle and the septum of the dorsal valve. 5. Cardinal view of the same specimen as fig. 4, showing also the extent of the area. 6. An oblique view of the interior of both valves, showing the septa and dental lamellve. PENTAMkR US (PENTAM }ERELLA) VENTRICOSUS, HALL. Page 382. FIGS. 7, 8. Dorsal and front views of an individual, showing the plications more distinctly than usual. PLEUROTO.MARIA OccIDENS, HALL. Page 392. FIG. 9. Lateral view of a very fine specimen, showing the external characters of the species. " 10. View of the aperture. This specimen is from the Niagara limestone of Lyons. Iowa, received from Dr. Farnsworth. PLEUROTOMARIA (TROCHONEMA) HOyI, HALL. Page 393. FiGs. 11, 12. Lateral and basal views of a specimen of this species, showing the surface strime and the wide umbilicus. TROCHofvENMA (CYCLONEXA?) PAUPER, HALL. Page 395. FIG. 13. Lateral view of a specimen in the collection of the Michigan University, at Ann Arbor, received under the name of Pleurotomaria Halei. CYRTOCERAS BREVICORNE, HALL. Page 407. FIG. 14. Lateral view of a specimen, showing the septa. TROCHOCERAS COSTA TuM, HALL. Page 402. FIG. 15. Lateral view of the upper surface, from a gutta-percha cast in the natural mould.