1835.] OF THE TERTIARY FORMATIONS.. 251 



denudation which the sea possesses, as shown by numberless facts, 

 it is not probable that a sedimentary deposit, when being upraised, 

 could pass through the ordeal of the beach, so as to be preserved in 

 sufficient masses to last to a distant period, without it were originally 

 of wide extent and of considerable thickness : now it is impossible on 

 a moderately shallow bottom, which alone is favourable to most living 

 creatures, that a thick and widely 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 movements of approxi- 

 mately contemporaneous subsidence are generally widely extensive, 

 as I am strongly inclined to believe from my examination of the Coral 

 Reefs of the great oceans or if, confining our view to South America, 

 the subsiding movements have been coextensive with those of elevation, 

 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, circum- 

 stances would have been favourable to the formation of fossiliferous 

 deposits, of wide extent and of considerable thickness ; and such 

 deposits, consequently, would have a good chance of resisting the 

 wear and tear of successive beach-lines, and of lasting to a future 

 epoch. 



May zist. 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 1 The rooms in Coquimbo swarm with them ; but 

 they will not live here at the height of only three or four thousand feet : 

 it can scarcely be the trifling diminution of temperature, but some 

 other cause which destroys these troublesome insects at this place. 

 The mines are now in a bad state, though they formerly yielded about 

 2,000 pounds in weight of silver a year. It has been said that "a 

 person with a copper-mine will gain ; with silver, he may gain ; but 

 with gold, he is sure to lose." This is not true : all the large Chilian 

 fortunes have been made by mines of the more precious metals. A 

 short time since an English physician returned to England from 

 Copiap6, taking with him the profits of one share in a silver-mine, 

 which amounted to about 24,000 pounds sterling. No doubt a copper- 

 mine with care is a sure game, whereas the other is gambling, or 

 rather taking a ticket in a lottery. The owners lose great quantities 

 of rich ores ; for no precautions can prevent robberies. I heard of a 

 gentleman laying a bet with another, that one of his men should rob 

 him before his face. The ore when brought out of the mine is broken 

 into pieces, and the useless stone thrown on one side. A couple of 

 the miners who were thus employed, pitched, as if by accident, two 

 fragments away at the same moment, and then cried out for a joke, 



