SERRA DO ESPINHAQO, BRAZIL 383 



and from there extends southward in a high ridge between the small 

 rivers Piabas and Una. This upper sedimentary part of the Para- 

 guassii basin is of rectangular shape, with its longest axis lying in 

 a north-south direction, and thus perpendicular to the general west- 

 east course of the middle and lower portions. It is characterized 

 topographically by secondary valleys extending from south to north 

 and from north to south, which unite their waters below Passagem, 

 and where the main valley assumes a general easterly direction. 



The geological structure of the first and lower plateau is fairly 

 well seen along the road from Bebedouro to Mocambo. At the first 



Fig. 5. — Profile near Santa Isabel. 



locality a fine escarpment, that extends southward as far as the eye 

 can reach, rises abruptly from the right bank of the river to an esti- 

 mated height of 250™. The base is composed of a horizontally 

 bedded, coarse, reddish sandstone. On a trail leading back among 

 the hills the sandstone is seen to rise to about 20™ above the river, 

 intercallations of micaceous sandy shale appearing near the top. 

 The section is then interrupted for a further rise of 40™, and then 

 comes a magnificent bluff of light-blue flaggy limestone about 40°^ 

 high. Some of the layers are full of cherty nodules, which on weather- 

 ing out of the rock afford a means of tracing it where concealed by a 

 soil-cap. At the Cachoeira do Funil, 6 kilometers above Bebedouro, 

 a similar escarpment, that stretches away to the northward, appears 



