—19 — 
rise insight of the Atlantic 150 kilometers south-west from Rio de 
Janeiro, and after flowing south-westward nearly to the Tieté, turn 
abruptly backward through an arc of 180°, and passing parallel to the 
former course, only a few kilometers distant, keep on to the north- 
east and enter the Atlantic, 200 kilometers north-east from Rio de 
Janeiro, is oneof the very interesting problemsin Brazilian physical 
geography whose solution has not yet been clearly demonstrated. 
The Tertiary (or older) fresh water deposits along the valley of the 
Parahyba near Taubaté which hold fossil fishes, etc., in its bituminous 
shales, may furnish the clue to its solution when carefully studied and 
mapped. 
It is possible that the curious course of the river as well as the 
origin of the deposits in question may be due to the great outflows of 
trap and basaltic material which covered such a large region of Brazil 
subsequent to the Triassic period, obstructing and forming lakes 
along many of the pre-Triassic rivers, diverting others into new 
channels and greatly modifying the older topography and preexisting 
river systems. 
