Sowerby, J. de C., and Dixon, F., 1850. The Geology and Fossils of the Tertiary and Cretaceous Formations of Sussex.
New Species-Group Names:
- amphiconus J. de C. Sowerby, 1850. pp. 102. 183. pl. viii. f. 7. 8.
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pyriformis J. de C. Sowerby, 1850. pp. 108. 189. pl. viii. f. 18.
