70 A JOURNEY IN BRAZIL. 
He comes upon a rock, for instance, or a rounded elevation 
which by its outline ha would suppose to be a " roche mou- 
tonnee," but approaching it more nearly he finds a decom- 
posed crust instead of a glaciated surface. It is the same 
with the loose materials corresponding to the drift of the 
Northern hemisphere, and with all boulders or detached 
masses of rock ; on account of their disintegration whei- 
ever they are exposed to the atmosphere, nothing is to 
be learned from their external appearance. There is not 
a natural surface of rock, unless recently broken, to be 
found anywhere. 
The sun had set before we drove into the pretty town 
of Petropolis, the summer paradise of all Rio Janeirans 
whose circumstances enable them to leave the heat and 
dirt and vile smells of the city, for the pure air and 
enchanting views of the Serra. In a central position 
stands the summer palace of the Emperor, a far gayer 
and more cheerful-looking edifice than the palace at San 
Christovao. Here he passes six months of the year. 
Through the midst of the town runs the pretty river 
Piabanha, a shallow stream, now rippling along in the 
bottom of its bed between high green banks ; but we 
were told that a night of rain in the hot season is enough 
to swell its waters till they overflow and flood the road. I 
could not but think how easy it would be for any one who 
cares to see tropical scenery to come here, when the direct 
line of steamers from New York is established, and, instead 
of going to Newport or Nahant, to take a house in Petropo- 
lis for the summer. It commands all the most beautiful 
scenery about Rio, and the horseback rides are without 
end. During our summer the weather is delightful here, 
just admitting a semblance of wood-fire morning and even- 
