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that practised at the mines of Jaragua. The proportion of gold pro- 

 duced was moderate : I was informed that it paid the master at the 

 rate of from fourteen pence to two shillings per day for each negro, 

 which is a large profit, as the daily subsistence of one costs somewhat 

 less than a penny. 



The sides of the ravine towards the top were bare, and of different 

 shades of colour, being tinged by the water which flows from the ve- 

 getable matter above : in the bottom, on the surface that was yet un- 

 worked, lay some huge, half-rounded, amorphous masses. In the 

 parts which had been worked, I observed two or three substances of 

 the same kind, which being too large to be moved, the earth which 

 imbedded them had been cut away, and they appeared like detached 

 nodules. On breaking a fragment from one of them with my ham- 

 mer, I was much surprised to find it a calcareous substance, a solid 

 mass composed of hexagonal crystals, with a small portion of brilliant 

 crystals of specular iron ore. I presented this fragment to the pro- 

 prietor, informing him that it was limestone, at which he was truly 

 astonished, having never before heard of stone lime * ; nor would he 

 believe me until I proved it by calcination. The mountains, as I 

 afterwards found, are of the same substance. 



As I stood observing the heavy operation of cutting and carrying 

 away the surface to get at the cascalhao, it occurred to me that much 

 time and labour might be saved by arching the work with brick ; 

 but, on suggesting the idea, I was informed that the sole or bottom 

 was quite decomposed, and subject to much water. 



There is reason to suppose that the stratum of limestone, below the 

 earth in the bottom of the valley, is of very modern formation, and 

 that, if not too thick to cut through, there might be found, between 

 it and the granite stratum underneath, a bed of cascalhao of prior 

 formation, much richer in gold than the upper stratum. 



* The little lime which they use here is made of shells, and is brought from Porto dos 

 Ca:(hes, 



