440 



NOTES ON BRAZIL. 



If asked why the same proportion of clay is not found below, I should 

 reply, it has probably been washed away by the superior moisture and 

 rains of the coast, and by the corrosion of streams, whose ravages are 

 proportioned to the length and angle of theii- fall. I have no system of 

 Geology to support ; I do not understand any ; but relate facts as they 

 appeared, and the impressions they made upon my mind, convinced that 

 nature operates here upon a scale scarcely reducible to the cir- 

 cumscribed phenomena observed in Great Britain and the Continent 

 of Europe. 



The Campo, or table land of Brazil, resting on this granitic core, is 

 composed of great masses of mountain, which appear to be detached 

 from each other, having between them broad basins, where the ground 

 is cut into deep ravines, and formed into strong undulations of three 

 to six hundred feet in height ; the sides of these ravines are exceedingly 

 steep, and their bottoms contain beds of torrents, so broken and generally 

 so difficult as to require bridges ; but the country has not yet advanced 

 far enough for the construction of many artificial roads. Hence the course 

 of travellers lies along the heads of ravines, the ridge of the hill 

 between them, even though it deviate to every point of the compass ; 

 here people meet with solid ground, and an uninterrupted course, though 

 the ridge is sometimes almost as narrow as the road which passes 

 along it, and the descent on either hand is rapid though not precipitous. 



As to the general soil of the country it is little different from that 

 Avhich has been already said to fill up the intervals between the granitic 

 cones, but in many places it has upon its surface a stratum of yellowish 

 brown clay, mixed with sand ; this covering lies in patches of various 

 dimensions, from nine to fifteen inches thick, and its edges are so worn 

 as plainly to indicate, that it was once much more extensive, perhaps 

 formed a superstratum to the whole present surface, that it is in a course 

 of wasting from rains, and will shortly disappear. Hence it is that in some 

 bottoms, and at the sides of gentle declivities, are sometimes found spots 

 of yellow sand almost as barren as the sea-beach, collected there by the 

 waters, while the other component part of the superstratum, being 



