102 NORTHERN CHILE. 



through the ordeal of the beach, so as to be pre- 

 served in sufficient masses to last to a distant j^eri- 

 od, without it were originally of wide extent, and 

 of considerable thickness : now it is impossible, on 

 a moderately shallow bottom, which alone is favour- 

 able to most living creatures, that a thick and wide- 

 ly extended covering of sediment could be spread 

 out, without the bottom sank down to receive the 

 successive layers. This seems to have actually 

 taken place at about the same period in southern 

 Patagonia and Chile, though these places are a 

 thousand miles apart. Hence, if prolonged move- 

 ments of approximately contemporaneous subsi- 

 dence are generally widely extensive, as I am 

 strongly inclined to believe from my examination of 

 the Coral Reefs of the gi-eat oceans — or if, confining 

 our view to South America, the subsiding move- 

 ments have been coextensive with those of eleva- 

 tion, by which, within the same period of existing 

 shells, the shores of Peru, Chile, Tierra del Fuego, 

 Patagonia, and La Plata have been upraised — then 

 we can see that at the same time, at far distant 

 points, circumstances would have been favourable 

 to the formation of fossiliferous deposits, of wide 

 extent and of considerable thickness ; and such de- 

 posits, consequently, would have a good chance of 

 resisting the wear and tear of successive beach- 

 lines, and of lasting to a future epoch. 



Marj 21st. — I set out in company with Don Jose 

 Edwards to the silver-mine of Arqueros, and thence 

 up the valley of Coquimbo. Passing through a 

 mountainous country, we reached by nightfall the 

 mines belonging to Mr. Edwards. I enjoyed my 

 night's rest here from a reason which will not be 

 fully appreciated in England, namely, the absence 

 of fleas! The rooms in Coquirnbo swarm with 



