250 



TRAVELS IN BRAZIL. 



foliated mica. The second is a coarse-grained 

 granite, with predominant greyish and reddish 

 white felspar, greyish white, and smoky quartz, 

 and a small portion of pinchbeck-brown and black 

 mica. It approximates the more nearly to the 

 graphic granite, as the felspar, in many places, has 

 the lustre of mother of pearl. The most beau- 

 tiful variety is a granite with much light reddish 

 grey felspar, small-grained smoky quartz, and im- 

 bedded in it single equi-angular six-sided prisms of 

 pinchbeck-brown mica of a middling size. The 

 granite about Rio de Janeiro, as is always the case 

 in similar mountains, often consists of earthy fel- 

 spar of a greyish colour, sometimes spotted of a 

 brownish yellow by oxyd of iron, smoky quartz, 

 and but a little black mica, and at the slightest 

 touch crumbling to pieces. The structure of the 

 granite gradually becomes slaty, because the smoky 

 quartz and the black small foliated mica (not so 

 much the smoky felspar) combine, and the rock 

 passes into gneiss. In this granite-gneiss pretty 

 large noble garnets are generally found imbedded, 

 and give it a beautiful appearance. It is chiefly 

 found near the city, for instance about the Sacco 

 d'Alferes ; but, according to the observation of our 

 friend and countryman, Mr. Von Eschwege, ap- 

 pears in many places along the sea-coast, and seems, 

 for example, in Ilha Grande, to alternate with the 

 granular granite. The latter is ofiten cut into 

 square stones in Rio de Janeiro, particularly in 



