486 
A JOURNEY IN BRAZIL. 
the boulders were universally decomposed and covered with 
a uniform crust, so that it was necessary to split them in 
order to ascertain their true nature. From distance to 
distance along the road were immense fragments of rock, 
sometimes twenty or thirty feet in height. These huge 
Garrafao, among the Organ Mountains. 
masses were frequently seen hanging on the brink of steep 
declivities, as if, having broken off from the heights above, 
and rolled down, they had been prevented from advancing 
farther by some obstacle, and had become gradually em- 
