chap. xii. Coquimbo. 403 



beds, represented in the following diagram (here given 

 again) by the letters F and E : — 



No. 37. 



Section of the Tertiary Formation at Coquimbo. 

 Surface of plain, 252 feet above sea. 

 .0 



Level of Sea. 



F — Lower Sandstone, with concretions and silicified bones, ) with fossil shells, all, or 

 E — Upper ferruginous sandstone, with numerous Balani, I nearly all, extinct. 

 and D— Calcareous beds with recent shells. A — Stratified sand in a ravine, also 

 with recent shells. 



I obtained good sections of bed (F) only in Herra- 

 dura Bay : it consists of soft whitish sandstone, with 

 ferruginous veins, some pebbles of granite, and concre- 

 tionary layers of hard calcareous sandstone. These 

 concretions are remarkable from the great number of 

 large silicified bones, apparently of cetaceous animals, 

 which they contain ; and likewise of a shark's teeth, 

 closely resembling those of the CarcJiarias megalodon. 

 Shells of the following species, of which the gigantic 

 Oyster and Perna are the most conspicuous, are nume- 

 rously embedded in the concretions : — 



1. Bulla ambigua, d'Orbig. * Voyage PaL' 



2. Monoceros Blainvillii, do. 



3. Cardium auca, do. 



4. Panopsea Coquimbensis, do. 



5. Perna Gaudichaudi, do. 



6. Artemis ponderosa ; Mr. Sowerby can find no distinguishing 



character between this fossil and the recent A. ponderosa ; it 

 is certainly an Artemis, as shown by the pallial impression. 



7. Ostrea Patagonica (?) Mr. Sowerby can point out no distin- 



guishing character between this species and that so eminently 

 characteristic of the great Patagonian formation; but he will 

 not pretend to affirm that they are identical. 



8. Fragments of a Venus and Natica. 



The cliffs on one side of Herradura Bay are capped 

 by a mass of stratified shingle, containing a little calca- 



