Rostellaria Gaudichaudi, d'Orbigny "Voyage" Pal. 2. Pectunculus Paytensis, d'Orbigny "Voyage" Pal. 3. Venus petitiana, d'Orbigny "Voyage" Pal. 4. Ostrea Patagonica? Sowerby from some of the varieties from Patagonia; though it would be hazardous to assert it is the same with that species, or with that from Coquimbo.

On the wide uninhabited plains of Patagonia another closely allied species, O. Patagonica of d'Orbigny, which frequents the valleys clothed with spiny bushes, is a wilder bird, and has a slightly different tone of voice.

Sowerby, with the Pyrula, the Venus meridionalis, the Crepidula gregaria, and the Turritella ambulacrum, and T. Patagonica. The evidence taken altogether indicates that this great tertiary formation is of considerable antiquity; but when treating of the Chilean beds, I shall have to refer again to this subject.

Out of these three beds, I procured the following twelve species, of which the two first were exceedingly numerous in individuals, as were the Terebratulae and Turritellae in certain layers: Ostrea Patagonica, d'Orbigny, "Voyage, Pal." Pecten Paranensis, d'Orbigny, "Voyage, Pal." Pecten geminatus, G.B. Sowerby. 5. Fusus Patagonicus, G.B. Sowerby. 8. Fusus Noachinus, G.B. Sowerby. 9.

Hence it is remarkable that four or five of the fossil shells from Navidad, namely, Voluta alta, Turritella Patagonica, Trochus collaris, Venus meridionalis, perhaps Natica solida, and perhaps the large oyster from Coquimbo, are considered by Mr. Sowerby as identical with species from Santa Cruz and P. Desire. M. d'Orbigny, however, admits the perfect identity only of the Trochus.

This bed rested on one with bones of an extinct rodent, namely, the Megamys Patagoniensis; and this again on another with extinct marine shells. The species found by M. d'Orbigny in different parts of this formation consist of: Ostrea Patagonica, d'Orbigny, "Voyage, Pal." Ostrea Ferrarisi, d'Orbigny, "Voyage, Pal." 3. Ostrea Alvarezii, d'Orbigny, "Voyage, Pal."

Olicancilleria Braziliensis d'Orbigny. 4. Olicancilleria auricularia, d'Orbigny. 5. Olivina puelchana, d'Orbigny. 6. Buccinanops cochlidium, d'Orbigny. 7. Buccinanops globulosum, d'Orbigny. 8. Colombella sertulariarum, d'Orbigny. 9. Trochus Patagonicus, and var. of ditto, d'Orbigny. 10. Paludestrina Australis, d'Orbigny. 11. Fissurella Patagonica, d'Orbigny. 12. Crepidula muricata, Lam. 13.

They belong to the very extensive family of coniferous plants, and have been named respectively Fitz-Roya Patagonica and Saxe-Gothea conspicua. There is also a remarkably handsome creeper, Hexacentras mysorensis, having pendent racemes of large flowers in shape resembling the snap-dragon, and of a rich orange and chocolate colour.

The limestone, where purest, is white, highly crystalline, and full of cavities: it includes small pebbles of quartz, broken shells, teeth of sharks, and sometimes, as I was informed, large bones: it often contains so much sand as to pass into a calcareous sandstone, and in such parts the great Ostrea Patagonica chiefly abounds.

The shells included in these beds have been named for me by M. d'Orbigny: they consist of: Ostrea Patagonica, d'Orbigny, "Voyage" Part. Pal. 2. Ostrea Alvarezii, d'Orbigny, "Voyage" Part. Pal. 3. Pecten Paranensis, d'Orbigny, "Voyage" Part. Pal. 4. Pecten Darwinianus, d'Orbigny, "Voyage" Part. Pal. 5. Venus Munsterii, d'Orbigny, "Voyage" Pal. 6. Arca Bonplandiana, d'Orbigny, "Voyage" Pal. 7.