chap. xii. Coquimbo to Copiapo. 405 



and no gradual transition in the nature of their organic 

 remains. Besides the fourteen species enumerated from 

 these two lower beds, M. d'Orbigny has described ten 

 other species given to him from this locality ; namely, 



1. Fusus Cleryanus, d'Orbig. 



' Voyage Pal/ 



2. petitianus, do. 



3. Venus hanetiana, do. 



4. incerta (?) do. 



5. Cleryana, do. 



6. Venus petitiana, d'Orbig. 



• Voyage Pal.' 



7. Chilensis, do. 



8. Solecurtus hanetianus, do. 



9. Mactra auca, do. 

 10. Oliva serena, do. 



Of these twenty-four shells, all are extinct, except, 

 according to Mr. Sowerby, the Artemis ponder osa, 

 Mytilus Chiloensis, and probably the great Balanus. 



Coquimbo to Copiapo. — A few miles north of Co- 

 quimbo, I met with the ferruginous, balaniferous mass 

 (E) with many silicified bones; I was informed that 

 these silicified bones occur also at Tonguay, south of 

 Coquimbo : their number is certainly remarkable, and 

 they seem to take the place of the silicified wood, so 

 common on the coast- formations of southern Chile. In 

 the valley of ChafLeral, I again saw this same formation, 

 capped with the recent calcareous beds. I here left 

 the coast, and did not see any more of the tertiary 

 formations, until descending to the sea at Copiapo : 

 here in one place I found variously coloured layers of 

 sand and soft sandstone, with seams of gypsum, and in 

 another place, a comminuted shelly mass, with layers 

 of rotten-stone and seams of gypsum, including many 

 of the extinct gigantic oyster : beds with these oysters 

 are said to occur at English Harbor, a few miles north 

 of Copiapo. 



Coast of Peru. — With the exception of deposits 

 containing recent shells and of quite insignificant 

 dimensions, no tertiary formations have been observed 

 on this coast, for a space of twenty-two degrees of lati- 

 tude north of Copiapo, until coming to Payta, where 



