It may be added that every one of the above-named genera from Quiriquina, which have an apparently tertiary character, are found in the Pondicherry strata. There are, however, some difficulties on this view of the formations at Concepcion being cretaceous, which I shall afterwards allude to; and I will here only state that the Cardium auca is found also at Coquimbo, the beds at which place, there can be no doubt, are tertiary.

NAVIDAD. (I was guided to this locality by the Report on M. Gay's "Geological Researches" in the "Annales des Scienc. Nat." 1st series tome 28.)

The Concepcion formation extends some distance northward, but how far I know not; for the next point at which I landed was at Navidad, 160 miles north of Concepcion, and 60 miles south of Valparaiso. The cliffs here are about eight hundred feet in height: they consist, wherever I could examine them, of fine-grained, yellowish, earthy sandstones, with ferruginous veins, and with concretions of hard calcareous sandstone. In one part, there were many pebbles of the common metamorphic porphyries of the Cordillera: and near the base of the cliff, I observed a single rounded boulder of greenstone, nearly a yard in diameter. I traced this sandstone formation beneath the superficial covering of gravel, for some distance inland: the strata are slightly inclined from the sea towards the Cordillera, which apparently has been caused by their having been accumulated against or round outlying masses of granite, of which some points project near the coast. The sandstone contains fragments of wood, either in the state of lignite or partially silicified, sharks' teeth, and shells in great abundance, both high up and low down the sea-cliffs. Pectunculus and Oliva were most numerous in individuals, and next to them Turritella and Fusus. I collected in a short time, though suffering from illness, the following thirty-one species, all of which are extinct, and several of the genera do not now range (as we shall hereafter show) nearly so far south:--

1. Gastridium cepa, G.B. Sowerby. 2. Monoceros, fragments of, considered by M. d'Orbigny as a new species. 3. Voluta alta, G.B. Sowerby (considered by M. d'Orbigny as distinct from the V. alta of Santa Cruz). 4. Voluta triplicata, G.B. Sowerby. 5. Oliva dimidiata, G.B. Sowerby. 6. Pleurotoma discors, G.B. Sowerby. 7. Pleurotoma turbinelloides, G.B. Sowerby. 8. Fusus subreflexus, G.B. Sowerby. 9. Fusus pyruliformis, G.B. Sowerby. 10. Fusus, allied to F. regularis (considered by M. d'Orbigny as a distinct species). 11. Turritella suturalis, G.B. Sowerby. 12. Turritella Patagonica, G.B. Sowerby (fragments of). 13. Trochus laevis, G.B. Sowerby. 14. Trochus collaris, G.B. Sowerby (considered by M. d'Orbigny as the young of the T. laevis). 15. Cassis monilifer, G.B. Sowerby. 16. Pyrula distans, G.B. Sowerby. 17. Triton verruculosus, G.B. Sowerby. 18. Sigaretus subglobosus, G.B. Sowerby. 19. Natica solida, G.B. Sowerby. (It is doubtful whether the Natica solida of S. Cruz is the same species with this.) 20. Terebra undulifera, G.B. Sowerby. 21. Terebra costellata, G.B. Sowerby. 22. Bulla (fragments of). 23. Dentalium giganteum, do. 24. Dentalium sulcosum, do. 25. Corbis (?) laevigata, do. 26. Cardium multiradiatum, do. 27. Venus meridionalis, do. 28. Pectunculus dispar, (?) Desh. (considered by M. d'Orbigny as a distinct species). 29, 30. Cytheraea and Mactra, fragments of (considered by M. d'Orbigny as new species). 31. Pecten, fragments of.

COQUIMBO.

(FIGURE 21. SECTION OF THE TERTIARY FORMATION AT COQUIMBO.

From Level of Sea to Surface of plain, 252 feet above sea, through levels F, E, D and C:

F.--Lower sandstone, with concretions and silicified bones, with fossil shells, all, or nearly all, extinct.

E.--Upper ferruginous sandstone, with numerous Balani, with fossil shells, all, or nearly all, extinct.

C and D.--Calcareous beds with recent shells.

A.--Stratified sand in a ravine, also with recent shells.)

For more than two hundred miles northward of Navidad, the coast consists of plutonic and metamorphic rocks, with the exception of some quite insignificant superficial beds of recent origin.

Charles Darwin

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