NOTES ON BRAZIL. 



603 



To contemplate the mines of Villa Rica with advantage, it will be 

 necessary to recollect that the land is composed of schist, or a sort of 

 slaty clay, resting upon a core of granite, gneiss, or sand-stone, some- 

 times laminated, at others solid, the gold being scattered in small 

 particles amidst the superjacent schist and clay ; and that the town is 

 placed at the junction of scA^-eral streams, whose waters have only one 

 outlet, by a narrow chasm, cut, by their force, through the surface 

 down to the more firm component parts. Before this outlet, called the 

 Rio do Carmo, became so deep as it is, a small lake must have 

 existed among the hills, through which all the waters of the upper 

 country passed, bringing with them, and depositing in the bottom, a 

 variety of heavy matter. Thus the ground seems to have been gradually 

 raised, while the outlet was deepened, until the water was entirely 

 drained off, and left the bottom dry, in the form of a level plain, 

 composed of all sorts of wreck, which, from the auriferous nature of the 

 country, contained a considerable proportion of gold, both in the form 

 of dust mingled with the attriturated schist and imbedded in quartz as 

 Cascalho. The extent of this plain is from thirty to forty acres, and it 

 is connected by narrow passes with others of a like size. The mountains 

 surrounding this supposed ancient lake, rise from seven hundred to a 

 thousand feet above its level, and on the declivity of the most Northerly 

 of them the city is built. In the sides of all of them much gold is 

 undoubtedly still detained, notwithstanding the quantity which has been 

 washed down or gathered from them. 



The comparatively small plain above mentioned may, however, be 

 considered as the swan, which, through a succession of years, has laid 

 golden eggs for the Crown of Portugal. Its surface is only just even 

 with the stream flowing through it, and after much rain it is always 

 flooded. A man then takes his station at the edge of the stream, 

 which, with all contained in it, seems to be regarded as public property, 

 and begins with a small hoe to open a trench, varying from one to three 

 feet in breadth, and about six inches deep, carefully throwing up the 

 earth on each side, so that no water may escape from it. He conducts 



