WOODWORTH: GEOLOGICAL EXPEDITION TO BRAZIL AND CHILE. 103 
corresponding there geologically to the Serra do Mar, and which has 
its watershed in the lofty crest of the Triassic escarpment on the 
west of the Permian belt of coal-bearing shales.1_ The Ypiranga, an 
affluent of the Bay of Paranagua, is apparently in the act of tapping 
the westward sloping surface of the planalto back of the Serra 
do Mar. 
According to Drs. Derby and Euzebio P. de Oliveira the Permian 
sandstone overlaps the Devonian shales at places in Parana and rises 
towards the crest of the Serra as at Vilha Vehla, a point of deeply 
disintegrated rocks southeast of Ponta Grossa, the name Vilha Vehla 
being applied in the same sense that “Rock City” is employed in 
North America. This ridge dies out northward in Sado Paulo and 
southwards in Parané so that in Santa Catharina the geologically 
higher escarpment of the trap plateau on the south comes in as the 
first range inside the coastal mountain belt. 
The relatively even sky-line of the Devonian cuesta forms a strik- 
ing feature in the treeless landscapes for many miles in Parana. 
The summit attains elevations exceeding 3,000 feet and approaches 
the level of the hypothetical Cretaceous peneplain out of the nearly 
level surface of which the lowlands between the ridges and plateaus 
of the planalto have been sculptured by Tertiary and more recent 
erosion. In northern Parana and southern Sao Paulo the topographic 
relief becomes complicated by the erosion of longitudinal valleys and 
by the association of ridges developed on the lower Permian sandstones 
which succeed on the west of the Devonian outcrop. The streams in 
this district also have cut deep gorges across these ridges apparently 
along lines of drainage inherited from the time when they flowed on 
the Cretaceous peneplain. Such appears to be the origin of the 
defile in the massive sandstones through which the Yapo flows in 
the country northwest from Castro to Tibagy. At Joachim Murinho 
Station the railway follows a broad gap in the sandstones which 
appears to have been once occupied by a river much larger than the 
present stream. The escarpment of the Devonian here becomes 
very irregular by reason of dissection. The steep sandstone cliffs 
form precipices overlooking lowlands excavated to the level of the 
crystalline rock-floor as at Pirahy. A characteristic view is to be had 
from Fabio Rego Station looking towards the cliffs of the Serra 
Morumgaba surmounted by the Morro do Chapeo. 
1 For some account of the Ribeira de Iguape with maps and plans see a report 
entitled Exploracio do Rio Ribeira de Iguape. Comm. Geog. e Geol. de 8S. Paulo, 
1908. 
