Triton verruculosus, G.B. Sowerby. 18. Sigaretus subglobosus, G.B. Sowerby. 19. Natica solida, G.B. Sowerby. Terebra undulifera, G.B. Sowerby. 21. Terebra costellata, G.B. Sowerby. 22. Dentalium giganteum, do. 24. Dentalium sulcosum, do. 25. Cardium multiradiatum, do. 27. Venus meridionalis, do. 28. Pecten, fragments of.

Several of the most tropical genera have no representative fossils at Navidad; and there are only single species of Cassis, Pyrula, and Sigaretus, two of Pleurotoma and two of Terebra, but none of these species are of conspicuous size. In Patagonia, there is even still less evidence in the character of the fossils, of the climate having been formerly warmer.

Accordingly, in the marls belonging to this period at Asti, Parma, Sienna, and parts of the Tuscan and Roman territories, we observe the genera Conus, Cypraea, Strombus, Pyrula, Mitra, Fasciolaria, Sigaretus, Delphinula, Ancillaria, Oliva, Terebellum, Terebra, Perna, Plicatula, and Corbis, some characteristic of tropical seas, others represented by species more numerous or of larger size than those now proper to the Mediterranean.

Pleurotoma : 34 to 43 30 : 2 18 St. Elena. Terebra : 34 : 5 Payta. Sigaretus : 34 to 44 30 : 12 Lima. Anomia : 30 : 7 48. Perna : 30 : 1 23 Xixappa. Artemis : 30 : 5 Payta. Voluta : 34 to 44 30 : Mr. Cuming does not know of any species living on the west coast, between the equator and latitude 43 south; from this latitude a species is found as far south as Tierra del Fuego.

The numerous shells from Navidad, with the exception of two, namely, the Sigaretus and Turritella found at Ypun, are likewise distinct from those found in any other part of this coast.

In the North-east Australian province, a different set of shells was dredged in similar depths, such as a Sigaretus, possibly new, Fissurella calyculata, Mitra obeliscus, a Turritella, a Murex, Columbella versicolor, and a new species off Cape York, Ranella pulchella, new, several Nassae, Phos senticosa and blainvillei, and sculptilis, in 3 and 5 fathoms, off Cape York; Strombus campbelli, in mud off Cape Upstart; Cerithium obeliscus, and a new species of the genus Obeliscus.