das Lombas, etc., which remain as outposts of a former coast 
line. 
Some remnants of this range reappear near Porto Alegre and 
it is probably the same system which curves westward from there 
under the name of Serra do Herval, etc., and passes on to the 
extreme southern point of Brazil. 
Westward from this range of granite and gneiss holding some 
belts of old metamorphic sediments, we have a broad plateau at the 
north which extends westward to the base of the Serra Geral, the 
peaks of which rise toa height of 1500 meters or more. The front 
escarpment of the Serra Geral is made by the outcrop of the massive 
cream colored conglomerates and red sandstones of the Trias capped 
above by great fiows of old eruptives, principally diabase much of it 
amygdaloidal in character. The Serra Geral is the summit of the 
divide separating the waters which flow westward into the Uruguay 
and Parana from those which pass eastward into the Atlantic. 
From the summit of the Serra Geral, there spreads out a wide 
plain known as theCampos, and it extends westward to the western 
boundary of the Republic, trenched of course by numerous rivers and 
their tributaries. 
Broad belts of this plain are covered with the Sao Bento or Triassic 
sandstone series, especially conspicuous in the higher mountain sum- 
mits of Rio Grande do Sul, Santa Catharina, Parana, and Sao Paulo. 
Rio Iguassu, a tributary of the Parana, north from Rio Uruguay, 
has cut back through the northward extension of the Serra Geral from 
Santa Catharina into the state of Paranda, and heads on the western 
slopes of the Serra do Mar, although the lofty summits of the moun- 
tainson either side of the Iguassu at Porto Unido, crowned with cliffs 
of Triassic sandstone and great flows of diabase, mark the true line of 
the Serra Geral which continues northward across Parana as the Serra 
da Esperanca, to be trenched again by Rio Ivahy at the great cascades 
below Therezina, and also by Rio Tibagy, and the waters of Rio Para- 
napanema, beyond which these lofty escarpments pass into the state of 
S. Paulo toward Botucatu. Still farther to the north-east, the Triassic 
escarpment is again trenched by Rio Tieté, Rio Mogyguassu and Rio 
Pardo, whose fountain streams, like those of the Paranapanema, rise 
on the old granite and crystalline complex far east of the Carboni- 
ferous rocks and cutting through the latter, pass westward into the 
waters of the Parana. 
The very unusual course of Rio Parahyba, whose head waters 
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