Hall, James, 1811-1898 / Geological survey of Wisconsin, 1859-1863. Palaeontology. Part third
Plate XVII, pp. [unnumbered]-Plate XVII PDF (666.5 KB)
PLATE XVII. ONCOCERAS ORCAS, HALL. Page 410. FIG. 1. Dorsal view of a large specimen. 2. Lateral view of the same. The figures are reduced to two-thirds the natural size. CIRTOCERAS DARDANUS, HALL. Page 406. FIG. 3. Lateral view of a specimen which preserves a part of the outer chamber and a small por- tion of the shell. " 4. Lateral view of an individual where the septa are not curved upward on the dorsal margin. 5. Transverse section of the specimen fig. 4. (JYRTOCERAS HERGCULES, WINCR. AND MAR. Page 409. FIG. 6. Lateral view of a large specimen which preserves a portion of the outer chamber, and also some of the surface strie near the lower end. c 7. Transverse section, showing the form of the shell. The two figures are reduced one- third in size.