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in Porlo Alegre, Rio Grande, Pelotas, Bagé, Santa Maria, and other 
of the larger towns in Rio Grande do Sul, while they have also 
been exported along the coast to Florianopolis, Itajahy, Paranagua, 
Santos, elc. These beds appear to be totally destitute of fossil ramains 
of any description, since in the many thousand square meters of 
pavement inspected in the cities where the flags have been used so 
extensively for side-walks not a single fossil has been observed. 
The massive beds near the top have been quarried for )uilding 
stone at several points along the Mogyana railway in S&o Paulo and 
especially in the summits west from Rio Pardo. They are also quarried 
along the Santa Maria & Uruguay railway. 
The higher sandstones, so frequently hardened and partially 
vitrified by contact with the eruptive rocks, often form picturesque 
walls, towers, and butes near the summits of elevated peaks, erosion 
having removed the softer beds below. Many of these topographic 
forms, especially in the state of Sado Paulo, resemble in some respects 
the great faulted blocks so conspicuous in the western portion of 
North America, and Dr. Orville A. Derby is inclined to ascribe the 
same origin to the block-like forms in S. Paulo. 
No conclusive evidence for such extensive faulting was observed 
among these same rocks and topographic forms in Parana, Santa 
Catharina, or Rio Grande do Sul, and ,henceit is possible that these 
block-like mountains are due entirely to erosion. 
The contact of the overlying diabase and basaltic eruptives with 
these sandstones is visible on Lhe Estrada Nova in Santa Catharina at 
an elevation of 748.2 meters, between the 19th and 20th kilometer 
from Minas. 
These massive sandstones make long lines of cliffs in the eastern 
face of the Serra Geral entirely across Santa Catharina, and Rio Grande 
do Sul, sinking gradually south-westward until they dip to water 
level at the Uruguay river near Itaquy on the Argentine boun- 
dary. 
It seems to be the gradual subsidence of this great sandstone 
deposit which causes the lowering and final disappearance of the 
Serra Geral to the south-west; in fact, they appear to form the 
basis of this mountain range at all points along its course. 
Where this mountain range is trenched and interrupted by Rio 
Iguassu. in the region of Porto da Unido, Paranda, these massive rocks 
